Bug 1571186 - Disable ExpirationTracker gtest on all OSX r=xpcom-reviewers,mccr8

We already had this disabled on debug but it still produces intermittents with no clear reason on opt. We still test this on other platforms so I want to go ahead and disable this outright until we can fix this properly. Followup filed in bug 1696959.

Differential Revision: https://phabricator.services.mozilla.com/D107500

xpcom/tests/gtest/moz.build

@@ -75,8 +75,8 @@ if CONFIG["OS_TARGET"] != "Android":
 if not (CONFIG["OS_TARGET"] == "WINNT" and CONFIG["CPU_ARCH"] == "aarch64"):
     UNIFIED_SOURCES += ["TestThreadUtils.cpp"]
 
-# skip the test on debug OSX due to frequent failures (bug 1571186)
-if not (CONFIG["MOZ_DEBUG"] and CONFIG["OS_TARGET"] == "Darwin"):
+# skip the test on OSX due to frequent failures (bug 1571186)
+if CONFIG["OS_TARGET"] != "Darwin":
     UNIFIED_SOURCES += ["TestExpirationTracker.cpp"]
 
 # skip the test on windows10-aarch64 and Android, aarch64 due to bug 1545670