Prior to this commit, we had configured separate test tasks for JUnit
and TestNG. In addition, we configured a standard `test` task that
depended on the `junit` and `testNG` tasks, and we had an additional
`aggregateTestReports` task that aggregated the reports from the JUnit
and TestNG test tasks.
Thanks to the introduction of the "TestNG Engine for the JUnit
Platform", this commit simplifies our Gradle build in the spring-test
module by running JUnit 4, JUnit Jupiter, and TestNG tests on the JUnit
Platform in a single Gradle `test` task.
See gh-27406
0b552a3534