Issue #26941: Fix test_threading that hangs on the Android armv7 qemu emulator.

Lib/test/test_threading.py

@@ -462,7 +462,7 @@ class ThreadTests(BaseTestCase):
         self.addCleanup(sys.setswitchinterval, old_interval)
 
         # Make the bug more likely to manifest.
-        sys.setswitchinterval(1e-6)
+        test.support.setswitchinterval(1e-6)
 
         for i in range(20):
             t = threading.Thread(target=lambda: None)