Attempt RLock creation prior to test execution on Linux, if it raises the...

Attempt RLock creation prior to test execution on Linux, if it raises the OSError in issue 3111, skip the test suite

Lib/test/test_multiprocessing.py

@@ -1755,9 +1755,12 @@ globals().update(testcases_threads)
 #
 
 def test_main(run=None):
-    if sys.platform.startswith("linux") and not os.path.exists("/dev/shm"):
-        from test.test_support import TestSkipped
-        raise TestSkipped("Missing required /dev/shm device on Linux!")
+    if sys.platform.startswith("linux"):
+        try:
+            lock = multiprocessing.RLock()
+        except OSError:
+            from test.test_support import TestSkipped
+            raise TestSkipped("OSError raises on RLock creation, see issue 3111!")
 
     if run is None:
         from test.test_support import run_unittest as run