Enable render test buildbot results on bot on chromium.android.

Attepted to enable this on an FYI bot. But that is unable to
successfully run chrome_public_test_apk due to some issue. Would
like to enable this on a bot already running chrome_public_test_apk
to see if it works as intended.

Review-Url: https://codereview.chromium.org/2626183002
Cr-Commit-Position: refs/heads/master@{#443114}

testing/buildbot/chromium.android.json

@@ -2911,6 +2911,7 @@
           "chrome_public_test_apk"
         ],
         "override_isolate_target": "chrome_public_test_apk",
+        "render_results_dir": "chrome/test/data/android/render_tests",
         "swarming": {
           "can_use_on_swarming_builders": true,
           "cipd_packages": [