Add OpenJDK 8 experimental support

Targeting 1.7: just adding support for the tools.

Various issues exist with OpenJDK 8: it doesn't build to completion
yet.

Change-Id: I54942f497264234e4bef488c8d17d243b4ef2f14
Merge "Add OpenJDK 8 experimental support"
Merge remote-tracking branch 'upstream/master'