GRAILS-11579 don't reset GrailsApplication instance after each test
use LinkedHashSet in place of List for loadedClasses in DefaultGrailsApplication to prevent duplicates in tests
use method actions in test controller
GRAILS-11581 Skip handling of method missing for the render method.
Merge branch '2.3.x' into 2.4.x

Conflicts:
	grails-plugin-gsp/src/ast/groovy/org/codehaus/groovy/grails/plugins/web/api/ControllerTagLibraryApi.java
GRAILS-11579 fix test, publish resetGrailsApplication event explicitly since that is intended behaviour in this test