Update chromium_mac recipe for re-imaged testers.

scripts/slave/recipes/chromium.expected/full_chromium_mac_Mac_Builder.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "chromium.mac",
       "--builder",
       "Mac Builder",
@@ skipping 89 matching lines @@
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/src/testing/buildbot/chromium.mac.json",
       "/path/to/tmp/json"
     ],
     "name": "read test spec",
     "~followup_annotations": [
       "@@@STEP_TEXT@path: [SLAVE_BUILD]/src/testing/buildbot/chromium.mac.json@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
-      "@@@STEP_LOG_LINE@json.output@  \"Mac10.6 Tests (1)\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"Mac10.6 Tests\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"gtest_tests\": [@@@",
       "@@@STEP_LOG_LINE@json.output@      {@@@",
       "@@@STEP_LOG_LINE@json.output@        \"swarming\": {@@@",
       "@@@STEP_LOG_LINE@json.output@          \"can_use_on_swarming_builders\": true@@@",
       "@@@STEP_LOG_LINE@json.output@        }, @@@",
       "@@@STEP_LOG_LINE@json.output@        \"test\": \"browser_tests\"@@@",
       "@@@STEP_LOG_LINE@json.output@      }@@@",
       "@@@STEP_LOG_LINE@json.output@    ]@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
-      "@@@STEP_LOG_LINE@json.output@  \"Mac10.7 Tests (1)\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"Mac10.8 Tests\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"gtest_tests\": [@@@",
       "@@@STEP_LOG_LINE@json.output@      {@@@",
       "@@@STEP_LOG_LINE@json.output@        \"swarming\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@          \"can_use_on_swarming_builders\": true@@@",
+      "@@@STEP_LOG_LINE@json.output@        }, @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"test\": \"browser_tests\"@@@",
+      "@@@STEP_LOG_LINE@json.output@      }@@@",
+      "@@@STEP_LOG_LINE@json.output@    ]@@@",
+      "@@@STEP_LOG_LINE@json.output@  }, @@@",
+      "@@@STEP_LOG_LINE@json.output@  \"Mac10.9 Tests\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@    \"gtest_tests\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@      {@@@",
+      "@@@STEP_LOG_LINE@json.output@        \"swarming\": {@@@",
       "@@@STEP_LOG_LINE@json.output@          \"can_use_on_swarming_builders\": true@@@",
       "@@@STEP_LOG_LINE@json.output@        }, @@@",
       "@@@STEP_LOG_LINE@json.output@        \"test\": \"browser_tests\"@@@",
       "@@@STEP_LOG_LINE@json.output@      }@@@",
       "@@@STEP_LOG_LINE@json.output@    ]@@@",
       "@@@STEP_LOG_LINE@json.output@  }@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
@@ skipping 94 matching lines @@
       "--build_revision",
       "170242",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"Mac Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.mac\", \"parent_buildername\": null, \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"Mac Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.mac\", \"parent_buildername\": null, \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
     "name": "package build"
   }
 ]