[3.15] gh-158539: Use the platform guard for in-process inspection tests

Author: pablogsal

Lib/test/test_external_inspection.py

@@ -3219,6 +3219,7 @@ def test_finally_no_exception_no_flag(self):
             self._check_exception_status(p, thread_tid, expect_exception=False)
 
 
+@skip_if_not_supported
 class TestExceptionDetectionInProcess(RemoteInspectionTestBase):
     """gh-158539: HAS_EXCEPTION for handlers running in generators/coroutines.