Try buffer option for XML test runner

Author: RReverser

test/runner.py

@@ -344,7 +344,8 @@ def run_tests(options, suites):
     output = open('out/test-results.xml', 'wb')
     import xmlrunner # type: ignore
     testRunner = xmlrunner.XMLTestRunner(output=output, verbosity=2,
-                                         failfast=options.failfast)
+                                         failfast=options.failfast,
+                                         buffer=True)
     print('Writing XML test output to ' + os.path.abspath(output.name))
   else:
     testRunner = unittest.TextTestRunner(verbosity=2, failfast=options.failfast)