Merge jdk-14+25

[Roman Kennke]

We haven't merged from upstream for a while. Let's do it now. Since
concurrent-class-unloading is now upstream, this brings the diff to zero.

List of changes:

http://cr.openjdk.java.net/~rkennke/upstream-jdk14-merge-2019-11-18/changesets.txt

There've been a few merge conflicts, which have been resolved by always
picking the incoming option. I also checked the diff to jdk-14+25 and
removed some whitespaces here and there to ensure it's completely clean.

Testing: hotspot_gc_shenandoah (x86_64 and x86_32)

Ok?

Roman