(shortfin) Parameterized pytest fixtures for testing over cpu and gpu

[renxida]

We should make better fixtures that would automatically replicate shortfin tests across CPU / GPU / multi-gpu / etc

Using this pytest hack:

# Dynamic Parameterization for lsys Fixture
def pytest_generate_tests(metafunc):
    if "generic_lsys" in metafunc.fixturenames:
        system = metafunc.config.getoption("--system")
        if system == "amdgpu":
            params = ["cpu", "amdgpu"]
        else:
            params = [system]
        metafunc.parametrize("generic_lsys", params, indirect=True)

We can make this fixture automatically test every test that uses it on not just CPU, but also GPU where available.

@pytest.fixture(scope="session")
def generic_lsys(request):
    system_type = request.param
    if system_type == "cpu" or system_type == "hostcpu":
        sc = sf.host.CPUSystemBuilder()
    elif system_type == "amdgpu":
        sc = sf.amdgpu.SystemBuilder()
    lsys = sc.create_system()
    yield lsys
    lsys.shutdown()