Revert of Convert ui_base_unittests to run exclusively on Swarming

testing/buildbot/chromium.win.json

Index: testing/buildbot/chromium.win.json
diff --git a/testing/buildbot/chromium.win.json b/testing/buildbot/chromium.win.json
index eb3640d27b6a780f4e049b6bfc7c1f9193d0b0c7..a3a338736fd0a8d2823eae0de73498aec83bc169 100644
--- a/testing/buildbot/chromium.win.json
+++ b/testing/buildbot/chromium.win.json
@@ -205,9 +205,6 @@
         "test": "sync_unit_tests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "ui_base_unittests"
       },
       {
@@ -467,9 +464,6 @@
         "test": "sync_unit_tests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "ui_base_unittests"
       },
       {
@@ -848,9 +842,6 @@
         "test": "sync_unit_tests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "ui_base_unittests"
       },
       {
@@ -1089,9 +1080,6 @@
         "test": "sync_unit_tests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "ui_base_unittests"
       },
       {
@@ -1488,9 +1476,6 @@
         "test": "sync_unit_tests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "ui_base_unittests"
       },
       {