Bug 1386079 - Disable gtest on windows nightly, it is permafailing because we PGO nightlies. r=jlorenzo

MozReview-Commit-ID: 2dCMfPnpeg4

--HG--
extra : rebase_source : ac26e00bf6b25fe7ab381244f0773e90e689de1e

taskcluster/ci/test/tests.yml

@@ -226,6 +226,7 @@ gtest:
         by-test-platform:
             linux64-qr/.*: ['mozilla-central', 'try']
             windows.*-pgo/.*: [] # permafails on pgo
+            windows.*-nightly/.*: [] # permafails on nightly too
             default: built-projects
     mozharness:
         script: desktop_unittest.py