Make components_browsertests swarmable and add to main waterfall. (2nd try)

testing/buildbot/chromium_trybot.json

 {
   "compile_targets": [
     "all"
   ],
   "gtest_tests": [
     {
       "test": "accessibility_unittests",
       "swarming": {
         "can_use_on_swarming_builders": true
       }
@@ skipping 48 matching lines @@
       "chromium_configs": [
         "chromium_chromeos",
         "chromium_chromeos_clang",
         "chromium_chromeos_ozone"
       ]
     },
     {
       "test": "chrome_elf_unittests",
       "platforms": ["win"]
     },
-    "components_browsertests",
+    {
+      "test": "components_browsertests",
+      "swarming": {
+        "can_use_on_swarming_builders": true
+      }
+    },
     {
       "test": "components_unittests",
       "swarming": {
         "can_use_on_swarming_builders": true
       }
     },
     {
       "test": "compositor_unittests",
       "platforms": ["linux", "win"]
     },
@@ skipping 203 matching lines @@
   "non_filter_tests_builders": [
   ],
 
   "filter_compile_builders": [
     "win_chromium_compile_dbg",
     "win_chromium_rel_swarming",
     "win_chromium_x64_rel_swarming",
     "win8_chromium_rel"
   ]
 }