Ensure aggregateTestReports task is UP-TO-DATE
Ensure aggregateTestReports task is UP-TO-DATE

Prior to this commit, the standard Gradle `test` task was configured to
execute all JUnit tests and had a dependency on the `testNG` task. In
addition, the `aggregateTestReports` task depended on the results of
the `test` and `testNG` tasks as input. Consequently, a subsequent
execution of the `aggregateTestReports` task would not be considered
UP-TO-DATE since the JUnit and TestNG results were both written to the
same "test" reports folder.

This commit introduces a new `junit` test task that allows JUnit and
TestNG test output to be completely independent. The standard `test`
task now depends on `junit` and `testNG` but does not execute any tests
itself, and the `aggregateTestReports` task now depends on the
individual `junit` and `testNG` results instead of on the mixed `test`
results.

See also: eec183ef2840d0e3cc20af01f69cda1adea7383e

spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework