Revert some changes made by 50c5a666 to JSP tests
refactor grails-web-jsp to support standalone usage, get rid of xpp dependency
use GrailsPlaceholderConfigurer and MapBasedSmartPropertyOverrideConfigurer in unit tests
execute all bean definition closures at once in GrailsApplicationTestPlugin
change references to normal refs
make GrailsWebApplicationContext support resolving GrailsApplication instance in tests
GRAILS-11314 Fix @Value in unit tests: use OptimizedAutowireCapableBeanFactory for GrailsWebApplicationContext by default