Prevent xla-build from clobbering pytorch_linux_trusty_py3_6_gcc5_4_test
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/23304
Test Plan: Imported from OSS
Differential Revision: D16459166
Pulled By: zou3519
fbshipit-source-id: 8f5c35ebf1fe6e86705e7fb4fff4c720bcd8f97b
