Move unit_tests from chromium_gtests to chromium_gtests_for_devices_with_graphical_output.

chromium_gtests_for_devices_with_graphical_output means "not cast".
The cast build doesn't include anything at the //chrome level, and
unit_tests lives at the //chrome level.

Currently we have unit_tests in chromium_gtests which runs on all bots,
and then an exception to remove it again on the cast bots.

Instead, put it in chromium_gtests_for_devices_with_graphical_output so that
it only runs on non-cast bots in the first place.

(It also ends up removing unit_tests from linux-blink-heap-incremental-marking
and linux-blink-heap-verification on the fyi waterfall, since these bots run
chromium_gtests instead of chromium_linux_gtests -- that looks like a bot
config bug, but it's only FYI bots anyways.)

This removes the last "unclear why" comment from test_suite*.pyl!

Bug: 843511,817779,812533
Change-Id: I76e0a2b30e0ca87c02c73cb46d8135d9ab7030d8
Reviewed-on: https://chromium-review.googlesource.com/1138333Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575339}

testing/buildbot/chromium.fyi.json

@@ -3481,12 +3481,6 @@
         },
         "test": "ui_touch_selection_unittests"
       },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "unit_tests"
-      },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
@@ -3753,12 +3747,6 @@
         },
         "test": "ui_touch_selection_unittests"
       },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "unit_tests"
-      },
       {
         "swarming": {
           "can_use_on_swarming_builders": true

testing/buildbot/test_suite_exceptions.pyl

@@ -1204,9 +1204,6 @@
   },
   'unit_tests': {
     'remove_from': [
-      # On chromium.linux, unclear why these aren't run on Cast.
-      'Cast Audio Linux',
-      'Cast Linux',
       # chromium.win
       'Win10 Tests x64 (dbg)',
     ],

testing/buildbot/test_suites.pyl

@@ -547,12 +547,6 @@
     'storage_unittests': {},
     'ui_base_unittests': {},
     'ui_touch_selection_unittests': {},
-    'unit_tests': {
-      'android_swarming': {
-        'hard_timeout': 900,
-        'shards': 5,
-      },
-    },
     'url_unittests': {},
     'webkit_unit_tests': {},
     'wtf_unittests': {},
@@ -571,6 +565,12 @@
         'hard_timeout': 900,
       },
     },
+    'unit_tests': {
+      'android_swarming': {
+        'hard_timeout': 900,
+        'shards': 5,
+      },
+    },
     'viz_unittests': {},
   },