increase shards for single_process_mash_interactive_ui_tests

Set shards to 3, as normal interactive_ui_tests does.

BUG=883523
TEST=none

Change-Id: Ia1fe3ec5e109b9d4b619c015525805e504e92d37
Reviewed-on: https://chromium-review.googlesource.com/c/1287197Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600591}

testing/buildbot/chromium.chromiumos.json

@@ -827,7 +827,8 @@
         ],
         "name": "single_process_mash_interactive_ui_tests",
         "swarming": {
-          "can_use_on_swarming_builders": true
+          "can_use_on_swarming_builders": true,
+          "shards": 3
         },
         "test": "interactive_ui_tests"
       },
@@ -1543,7 +1544,8 @@
         ],
         "name": "single_process_mash_interactive_ui_tests",
         "swarming": {
-          "can_use_on_swarming_builders": true
+          "can_use_on_swarming_builders": true,
+          "shards": 3
         },
         "test": "interactive_ui_tests"
       },

testing/buildbot/chromium.memory.json

@@ -4647,7 +4647,8 @@
         ],
         "name": "single_process_mash_interactive_ui_tests",
         "swarming": {
-          "can_use_on_swarming_builders": true
+          "can_use_on_swarming_builders": true,
+          "shards": 3
         },
         "test": "interactive_ui_tests"
       },
@@ -5983,7 +5984,8 @@
               "cpu": "x86-64",
               "os": "Ubuntu-14.04"
             }
-          ]
+          ],
+          "shards": 3
         },
         "test": "interactive_ui_tests"
       },

testing/buildbot/test_suites.pyl

@@ -1762,6 +1762,9 @@
           '--enable-features=SingleProcessMash',
           '--test-launcher-filter-file=../../testing/buildbot/filters/chromeos.single_process_mash.interactive_ui_tests.filter',
         ],
+        'swarming': {
+          'shards': 3,
+        },
       },
       'ui_chromeos_unittests': {},
       'views_mus_unittests': {},