Explicitly close the subprocess' stdout stream when we're done with it.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxPython/Phoenix/trunk@74366 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

unittests/runtests.py

@@ -89,6 +89,7 @@ class MyTestSuite(unittest.TestSuite):
             #    output = output.decode('ascii') 
             output = output.rstrip()
             rval = sp.wait()
+            sp.stdout.close()
             if rval:
                 print("Command '%s' failed with exit code %d." % (cmd, rval))
                 sys.exit(rval)