ART-tests: remove DX dependency from 706-checker-scheduler.

With the D8 generated code 2 PHI instruction are swapped in the ARM64
code. This CL updates the corresponding CHECK conditions and enables
D8.

Test: art/test.py -b -r --target -t 706-checker-scheduler
Bug: 65168732
Change-Id: If17bfdd0732b850279a10736c15ef296e15f0c90
2 files changed