- Rename app_test_i2s_loopback to test_i2s_loopback

- Port test_i2s_loopback from xmostest to pytest and test_support

tests/conftest.py

@@ -0,0 +1,9 @@
+import pytest
+
+def pytest_addoption(parser):
+    parser.addoption("--enabletracing", action="store_true", default=False, help="Enable xsim tracing")
+
+
+@pytest.fixture
+def options(request):
+    yield request.config.option