RFC: Pick up 9.0.4 to sh/jdk9

[Aleksey Shipilev]

Upstream jdk-updates/jdk9u had pushed the changesets for 9.0.4:
  http://hg.openjdk.java.net/jdk-updates/jdk9u

Let's pick them up! A few trivial merges were needed.

Testing: hotspot_gc_shenandoah {fastdebug|release}

Thanks,
-Alekse