RFC: jdk10/hs (jdk10+22) merge

[Aleksey Shipilev]

jdk10/hs is now closed for consolidation. According to our plan, we need to pick up the outstanding
changes from there for our own stabilization, before we could do the monorepo move.

Merge stats:
  538 files changed, 9972 insertions(+), 8947 deletions(-)

Most of that is Graal update. Atomic refactoring to templates required some changes in Shenandoah
code, adding type casts here and there. Removal of oop->is_oop in favor of oopDesc::is_oop required
touchups. There is at least one place with a new SATB hook, rewritten to
bs()->keep_alive_barrier(...) now.

Testing: hotspot_gc_shenandoah

Thanks,
-Aleksey