RFR: Re-add Shenandoah TLAB allocation in aarch64 assembly

[Aleksey Shipilev]

On 07/10/2018 11:28 AM, Roman Kennke wrote:
> Sorry, little mistake, please review this one:
> http://cr.openjdk.java.net/~rkennke/aarch64-tlab/webrev.02/

Looks good. Verified on RPi3/AArch64 with -Xint.

-Aleksey