win: add --return-nonzero-on-failures to sc_testpilot

Summary:
For whatever reason, sc_testpilot default to --return-zero-on-failures, which
means that test failures are simply not reported properly to the signal box.
Fix that by explicitely passing --return-nonzero-on-failures

Reviewed By: fanzeyi

Differential Revision: D29509158

fbshipit-source-id: ef991f91df48e99769f96ffd8d7015cdf507c723

Author: xavierd

build/fbcode_builder/getdeps/builder.py

@@ -741,6 +741,7 @@ def list_tests():
                     "--test-config",
                     "platform=%s" % machine_suffix,
                     "buildsystem=getdeps",
+                    "--return-nonzero-on-failures",
                 ]
             else:
                 testpilot_args = [