[PGO] Add REQUIRES to test (#169531)
The test was added by b8ef25aa643761233dc5b74d9fb7c38a2064d9c7. It
failed on at least the following bots, but the failure did not reproduce
on my test machines or in pre-commit CI:
- https://lab.llvm.org/buildbot/#/builders/190/builds/31643
- https://lab.llvm.org/buildbot/#/builders/65/builds/25949
- https://lab.llvm.org/buildbot/#/builders/154/builds/24417
d69e70149636efa0293310303878fbf9a5f31433 did not fix the failure.
Hopefully this will.
