Adds test.support.PGO and skips tests that are not useful for PGO.
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 2bfb69c..0906606 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -21,6 +21,9 @@
 except ImportError:
     threading = None
 
+if support.PGO:
+    raise unittest.SkipTest("test is not helpful for PGO")
+
 mswindows = (sys.platform == "win32")
 
 #