Revert of Disable telemetry tests for Mac 10.9. (patchset #2 id:20001 of...

Revert of Disable telemetry tests for Mac 10.9. (patchset #2 id:20001 of https://codereview.chromium.org/706703003/)

Reason for revert:
Second attempt to re-enable tests. I think there may still be one test failure, but we can disable that one test. If there's more than one, revert this.

Original issue's description:
> Disable telemetry tests for Mac 10.9.
>
> The telemetry tests are failing consistently on OSX 10.9.
>
> BUG=420615
> R=tonyg@chromium.org
>
> Committed: https://crrev.com/5503de1eeae0437c1f8160d69b04d6241bc5e974
> Cr-Commit-Position: refs/heads/master@{#303114}

TBR=phajdan.jr@chromium.org,tonyg@chromium.org,garykac@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=420615

Review URL: https://codereview.chromium.org/744283002

Cr-Commit-Position: refs/heads/master@{#305096}

testing/buildbot/chromium.mac.json

@@ -279,6 +279,14 @@
       "url_unittests"
     ],
     "scripts": [
+      {
+        "name": "telemetry_unittests",
+        "script": "telemetry_unittests.py"
+      },
+      {
+        "name": "telemetry_perf_unittests",
+        "script": "telemetry_perf_unittests.py"
+      },
       {
         "name": "nacl_integration",
         "script": "nacl_integration.py"
@@ -370,6 +378,14 @@
       "url_unittests"
     ],
     "scripts": [
+      {
+        "name": "telemetry_unittests",
+        "script": "telemetry_unittests.py"
+      },
+      {
+        "name": "telemetry_perf_unittests",
+        "script": "telemetry_perf_unittests.py"
+      },
       {
         "name": "nacl_integration",
         "script": "nacl_integration.py"