Use external repository mirrors in build (#6094) We've been bitten by external repository fluctuation for a long time. This PR makes most of tests use repository mirrors set up by ourselves via init script and system property.
There're still some tests not switching to mirrors, which would be fixed in follow-up commits.
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`.