Ignore flaky Play tests pending removal of Play support The Gradle Play support has been extracted to an external plugin: https://github.com/gradle/playframework. The intent is to announce this new plugin, and remove Play support from the core.
In light of this, I'm ignoring these flaky tests rather than trying to fix them.
Re-enable Play/Scala tests on Java 9+ (#5593) Almost all Play/Scala tests were ignored on Java 9/10, which makes it lack coverage. This PR does:
- Update Scala version to Java9-compatible version according to [JDK compatibility](https://docs.scala-lang.org/overviews/jdk-compatibility/overview.html). - Update default Play version to latest 2.6.15, which supports Java 9/10 - Adjust corresponding samples. Previous default Play version 2.3.10 was too old (release at 2014). - Ignored the tests which can't work on Java 9+. - Separate Play test resources with different versions. For example, Play 2.6 uses `build.gradle` and `Play 2.4/2.5` uses `build.gradle.old`. - Previously `AbstractMultiVersionPlayContinuousBuildIntegrationTest` didn't have `targetPlatform` configuration, which made multi-version tests meaningless - Fix `play-logback` configuration for `2.5.18`.