[UR] Move conformance tests over to lit (#17998)
Conformance tests are now ran by LLVM's lit framework rather than ctest.
A new `check-unified-runtime-conformance` target is available, which
builds and runs all conformance tests. The `test` target will still run
them.
Some additional housekeeping was done:
* `add_conformance_test_with_x_environment` was renamed to
`add_conformance_x_test`.
* Conformance tests now explicitly respect `ONEAPI_DEVICE_SELECTOR`.
* If unspecified, `ONEAPI_DEVICE_SELECTOR` will now be populated with
the list of built targets. Notably, this will exclude adapters which
exist in the build directory but were not specified using a
`BUILD_ADAPTER` cmake option (e.g, from a previous build before a
reconfigure).
* References to `UR_CTS_ADAPTER_PLATFORM` and `UR_CTS_BACKEND` are
removed (they never did anything anyway).
* Github build jobs have been updated.
* The generated gtest binaries have been moved from `build/bin` to
`build/test/conformance`
* `requirements_testing.txt` now imports psutil for using timeouts.
* Output format has been changed to show a progress bar and print
the test output in real time.
* Testing now respects the "device" filters from
`ONEAPI_DEVICE_SELECTOR` (previously, the filter was only used to
select the platform. `opencl:cpu` now works as expected.
* Some CUDA tests are marked as failing since they are failing
after this change.
As a resut of these changes, a build with both the v1 and v2
versions of the level zero adapter will only run the v2 adapter.
Building with only one version of the level zero adapter (as the
Github CI currently does) works as expected and only runs that
version.
