Revert of Enable Mac headless tests now that headless targets are included on Mac build.

testing/buildbot/chromium.mac.json

Index: testing/buildbot/chromium.mac.json
diff --git a/testing/buildbot/chromium.mac.json b/testing/buildbot/chromium.mac.json
index 643a90a82994d8fed038410587aba2e73f5af464..110220c5b44970eb11e7a8bca55387fdd31976d1 100644
--- a/testing/buildbot/chromium.mac.json
+++ b/testing/buildbot/chromium.mac.json
@@ -175,28 +175,6 @@
       },
       {
         "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "headless_browsertests"
-      },
-      {
-        "args": [
-          "--enable-browser-side-navigation"
-        ],
-        "name": "browser_side_navigation_headless_browsertests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "headless_browsertests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "headless_unittests"
-      },
-      {
-        "swarming": {
           "can_use_on_swarming_builders": false
         },
         "test": "interactive_ui_tests"