AutoConfigurationReport shows duplicate messages

Below is a report while I was converting a guide to M6. There are clearly duplicate outcomes, like `MultipartAutoConfiguration` and `EmbeddedServletContainerAutoConfiguration.EmbeddedTomcat`. It might be due to either the wrong equals/hashcode for `Outcome`, or in case the report doesn't use a Set to filter out duplicate entries.
```
=========================
AUTO-CONFIGURATION REPORT
=========================


Positive matches:
-----------------

   MessageSourceAutoConfiguration
      - @ConditionalOnMissingBean (types: org.springframework.context.MessageSource; SearchStrategy: all) found no beans (OnBeanCondition)

   PropertyPlaceholderAutoConfiguration#propertySourcesPlaceholderConfigurer
      - @ConditionalOnMissingBean (types: org.springframework.context.support.PropertySourcesPlaceholderConfigurer; SearchStrategy: current) found no beans (OnBeanCondition)

   DispatcherServletAutoConfiguration
      - found web application StandardServletEnvironment (OnWebApplicationCondition)
      - @ConditionalOnClass classes found: org.springframework.web.servlet.DispatcherServlet (OnClassCondition)
      - found web application StandardServletEnvironment (OnWebApplicationCondition)
      - @ConditionalOnClass classes found: org.springframework.web.servlet.DispatcherServlet (OnClassCondition)
      - @ConditionalOnBean (types: org.springframework.boot.context.embedded.EmbeddedServletContainerFactory; SearchStrategy: all) found the following [tomcatEmbeddedServletContainerFactory] (OnBeanCondition)

   DispatcherServletAutoConfiguration#dispatcherServlet
      - no DispatcherServlet found (DispatcherServletAutoConfiguration.DefaultDispatcherServletCondition)

   EmbeddedServletContainerAutoConfiguration
      - found web application StandardServletEnvironment (OnWebApplicationCondition)
      - found web application StandardServletEnvironment (OnWebApplicationCondition)

   EmbeddedServletContainerAutoConfiguration.EmbeddedTomcat
      - @ConditionalOnClass classes found: javax.servlet.Servlet,org.apache.catalina.startup.Tomcat (OnClassCondition)
      - @ConditionalOnClass classes found: javax.servlet.Servlet,org.apache.catalina.startup.Tomcat (OnClassCondition)
      - @ConditionalOnMissingBean (types: org.springframework.boot.context.embedded.EmbeddedServletContainerFactory; SearchStrategy: current) found no beans (OnBeanCondition)

   ServerPropertiesAutoConfiguration#serverProperties
      - @ConditionalOnMissingBean (types: org.springframework.boot.context.embedded.properties.ServerProperties; SearchStrategy: all) found no beans (OnBeanCondition)

   WebMvcAutoConfiguration
      - found web application StandardServletEnvironment (OnWebApplicationCondition)
      - @ConditionalOnClass classes found: javax.servlet.Servlet,org.springframework.web.servlet.DispatcherServlet,org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter (OnClassCondition)
      - found web application StandardServletEnvironment (OnWebApplicationCondition)
      - @ConditionalOnClass classes found: javax.servlet.Servlet,org.springframework.web.servlet.DispatcherServlet,org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter (OnClassCondition)
      - @ConditionalOnMissingBean (types: org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; SearchStrategy: all) found no beans (OnBeanCondition)

   WebMvcAutoConfiguration#hiddenHttpMethodFilter
      - @ConditionalOnMissingBean (types: org.springframework.web.filter.HiddenHttpMethodFilter; SearchStrategy: all) found no beans (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#defaultViewResolver
      - @ConditionalOnMissingBean (types: org.springframework.web.servlet.view.InternalResourceViewResolver; SearchStrategy: all) found no beans (OnBeanCondition)


Negative matches:
-----------------

   RabbitAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.amqp.rabbit.core.RabbitTemplate,com.rabbitmq.client.Channel (OnClassCondition)

   AopAutoConfiguration
      - required @ConditionalOnClass classes not found: org.aspectj.lang.annotation.Aspect,org.aspectj.lang.reflect.Advice (OnClassCondition)

   BatchAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.batch.core.launch.JobLauncher (OnClassCondition)

   JpaRepositoriesAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.data.jpa.repository.JpaRepository (OnClassCondition)

   MongoRepositoriesAutoConfiguration
      - required @ConditionalOnClass classes not found: com.mongodb.Mongo,org.springframework.data.mongodb.repository.MongoRepository (OnClassCondition)

   DataSourceAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType (OnClassCondition)

   DataSourceTransactionManagerAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.jdbc.core.JdbcTemplate (OnClassCondition)

   JmsTemplateAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.jms.core.JmsTemplate,javax.jms.ConnectionFactory (OnClassCondition)

   DeviceResolverAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.mobile.device.DeviceResolverHandlerInterceptor,org.springframework.mobile.device.DeviceHandlerMethodArgumentResolver (OnClassCondition)

   HibernateJpaAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean,javax.persistence.EntityManager,org.hibernate.ejb.HibernateEntityManager (OnClassCondition)

   ReactorAutoConfiguration
      - required @ConditionalOnClass classes not found: reactor.spring.context.config.EnableReactor (OnClassCondition)

   ThymeleafAutoConfiguration
      - required @ConditionalOnClass classes not found: org.thymeleaf.spring3.SpringTemplateEngine (OnClassCondition)

   EmbeddedServletContainerAutoConfiguration.EmbeddedJetty
      - required @ConditionalOnClass classes not found: org.eclipse.jetty.server.Server,org.eclipse.jetty.util.Loader (OnClassCondition)

   MultipartAutoConfiguration
      - @ConditionalOnClass classes found: javax.servlet.Servlet,org.springframework.web.multipart.support.StandardServletMultipartResolver (OnClassCondition)
      - @ConditionalOnClass classes found: javax.servlet.Servlet,org.springframework.web.multipart.support.StandardServletMultipartResolver (OnClassCondition)
      - @ConditionalOnBean (types: javax.servlet.MultipartConfigElement; SearchStrategy: all) found no beans (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#beanNameViewResolver
      - @ConditionalOnBean (types: org.springframework.web.servlet.View; SearchStrategy: all) found no beans (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#viewResolver
      - @ConditionalOnBean (types: org.springframework.web.servlet.View; SearchStrategy: all) found no beans (OnBeanCondition)

   WebSocketAutoConfiguration
      - required @ConditionalOnClass classes not found: org.springframework.web.socket.WebSocketHandler (OnClassCondition)
```