RFR 8191986: TLAB refills for Aarch64

[JC Beyler]

Hi all,

The TLAB and the inline contiguous allocations handling are different
for each architecture. On certain architectures, TLAB is never
actually never refilled (ref:
https://bugs.openjdk.java.net/browse/JDK-8190862).

The idea behind the implementation for Aarch64 is the same as for
Sparc/X86/Arm and is to do one thing:
  - separate TLAB usage to contiguous allocations in eden space.

Bug: https://bugs.openjdk.java.net/browse/JDK-8191986
WebRev: http://cr.openjdk.java.net/~rasbold/8191986/webrev.02/

Does anyone see any issues with this webrev? Could someone test/verify
it please?

Thanks for your help,
Jc