Check JHP is enabled only once during TLAB allocation

The check whether JHP is enabled or not involves loading an atomic with
acquire order. During TLAB allocation it happens twice for region-space
and thrice for bump-pointer-space.

Bug: 310655393
Test: manual
Change-Id: If13cf7e136fdc7da1643fe0bd2755adbcc2bbd9f
3 files changed