run-tests: self-test on Windows needs binary streams

tests/run-tests.py

@@ -1820,4 +1820,13 b' class TestRunner(object):'
 
 if __name__ == '__main__':
     runner = TestRunner()
+
+    try:
+        import msvcrt
+        msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
+        msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
+        msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
+    except ImportError:
+        pass
+
     sys.exit(runner.run(sys.argv[1:]))