RFC: Pick up 11.0.8+1 to sh/jdk11

[Aleksey Shipilev]

Upstream had published 11.0.8+1, let's pick it up to sh/jdk11.

The merge was simple, except one thing. I had to apply the missing Shenandoah hunk from 8231550 to
unbreak the tests:
  https://hg.openjdk.java.net/jdk/jdk/rev/bada0782842a

I will tag it shenandoah-jdk-11.8.0+1 after some post-integration testing.

Testing: hotspot_gc_shenandoah {fastdebug, release}

-- 
Thanks,
-Aleksey