[compiler-rt] Support unit tests for the GPU build (#187895)
Summary:
This PR enables the basic unit tests for builtins to be run on the GPU
architectures. Other targets like profiling are supported, but the
host-device natures will make it more difficult to adequately unit
test. It may be be possible to do basic tests there, to simply verify
that
counters are present and in the proper format for when they are copied
to the host.