RFC/RFR: Pick up jdk-11.0.3+6 to sh/jdk11

[Aleksey Shipilev]

Upstream^W We have pushed the jdk-11.0.3+6 tag upstream to jdk-updates/jdk11u. Let's pick it up to
sh/jdk11. The merge is trivial, and includes a single x86_32 fix, plus some accidental commit and
reversal.

Summary of changes:
  http://cr.openjdk.java.net/~shade/shenandoah/merges/jdk11-11.0.3%2b6/changesets.txt

Webrev:
  http://cr.openjdk.java.net/~shade/shenandoah/merges/jdk11-11.0.3%2b6/webrev.01/

Since this is the trivial merge, I plan to skip any further testing, and just tag
itshenandoah-jdk-11.0.3+6 right away.

Testing: x86_64 {fastdebug|release} tier1_gc_shenandoah

Thanks,
-Aleksey