Bug 1562745 - Make OSX10.14 debug tests actually use debug builds. r=jmaher

As far as I can tell, the intermittent suite_start failures are due to
stdout/stderr output interleaving -- a known issue for reftest logging,
without a clear way forward. Let's work around it the same way we did
on Windows.

Differential Revision: https://phabricator.services.mozilla.com/D37023

--HG--
extra : moz-landing-system : lando

layout/tools/reftest/runreftest.py

@@ -765,7 +765,7 @@ class RefTest(object):
             'processOutputLine': [self.outputHandler],
         }
 
-        if mozinfo.isWin:
+        if mozinfo.isWin or mozinfo.isMac:
             # Prevents log interleaving on Windows at the expense of losing
             # true log order. See bug 798300 and bug 1324961 for more details.
             kp_kwargs['processStderrLine'] = [self.outputHandler]

taskcluster/ci/test/reftest.yml

@@ -90,8 +90,8 @@ jsreftest:
             linux64-qr/opt: 4
             linux64-qr/debug: 5
             linux64/debug: 5
-            macosx.*-64-ccov/debug: 5
-            macosx.*-64(-shippable)?/.*: 2
+            macosx.*-64(-ccov)/debug: 5
+            macosx.*-64(-shippable)?/opt: 2
             default: 3
     max-run-time:
         by-test-platform:

taskcluster/ci/test/test-platforms.yml

@@ -283,7 +283,7 @@ macosx1014-64-shippable/opt:
         - web-platform-tests-wdspec-headless
 
 macosx1014-64/debug:
-    build-platform: macosx64-shippable/opt
+    build-platform: macosx64/debug
     test-sets:
         - macosx1014-64-tests
         # - marionette-media-tests