Match Playstore version for AR tests

Modifies the swarming dimensions used for AR instrumentation tests to
match against Playstore version. The AR tests fail if the installed
Playstore version is too old, so we want to ensure that we're running
on a known-good version.

Bug: 914927
Change-Id: I3cc3b1c74aa75b9d9040e26e9eb8a969b465eaa7
Reviewed-on: https://chromium-review.googlesource.com/c/1429179
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625247}

testing/buildbot/chromium.android.json

@@ -17211,6 +17211,7 @@
           "dimension_sets": [
             {
               "device_os": "OPR3.170623.008",
+              "device_playstore_version": "12.8.23-all",
               "device_type": "marlin",
               "os": "Android"
             }

testing/buildbot/test_suite_exceptions.pyl

@@ -663,6 +663,25 @@
       },
     },
   },
+  'monochrome_public_test_ar_apk': {
+    'modifications': {
+      # chromium.android
+      # We need to match the Playstore version as well because AR tests fail on
+      # old versions of the Playstore.
+      'Oreo Phone Tester': {
+        'swarming': {
+          'dimension_sets': [
+            {
+              'device_os': 'OPR3.170623.008',
+              'device_playstore_version': '12.8.23-all',
+              'device_type': 'marlin',
+              'os': 'Android',
+            },
+          ],
+        },
+      },
+    },
+  },
   'nacl_helper_nonsfi_unittests': {
     'remove_from': [
       # chromium.memory