Fix LSE reference atomics for heap poisoning.

Test: Build with `ART_HEAP_POISONING=true`, then
      testrunner.py --target --64 --optimizing -t 712
Bug: 461125269
Flag: EXEMPT BUGFIX
Change-Id: Id5a3c0013ea75927ab687a9338d2b82c4d853ac4
1 file changed