[aarch64-port-dev ] [11u] RFR 8228400: Remove built-in AArch64 simulator

[Aleksey Shipilev]

Original change:
  https://bugs.openjdk.java.net/browse/JDK-8228400
  https://hg.openjdk.java.net/jdk/jdk/rev/01bca26734bb

This train goes all the way down to 8u-aarch64, this change is for 11u. This considerably shrinks
the aarch64 code, making it more maintainable. I'll let the original change stew in jdk/jdk a little
bit more, but we can start reviewing backports meanwhile. If there are follow-up issues from that
removal, we would address them as separate backports (as usual).

11u webrev:
  https://cr.openjdk.java.net/~shade/8228400/webrev.11u.01/

There are several differences:
  - no shenandoahBarrierSetAssembler.hpp; we would discover the blrt removal during downstream
Shenandoah merges (and build failures);
  - os_linux_aarch64.cpp is a bit different: has SPELL_REG_{SP,FP} and thus conflicts;
  - a few BUILTIN_SIM blocks removals were rejected due to context changes;

Testing: aarch64 tier1, tier2; eyeballing differences against jdk/jdk changeset

-- 
Thanks,
-Aleksey