Add mb config for CrWinClang64(dbg).

testing/buildbot/chromium.fyi.json

Index: testing/buildbot/chromium.fyi.json
diff --git a/testing/buildbot/chromium.fyi.json b/testing/buildbot/chromium.fyi.json
index b7067882df0bb5fd7c8311eb31819ff1a41c7d44..90a6ad83f378f1eebea1a3ed458a32b0b9cd1d72 100644
--- a/testing/buildbot/chromium.fyi.json
+++ b/testing/buildbot/chromium.fyi.json
@@ -2366,16 +2366,9 @@
         "test": "angle_unittests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "base_unittests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "shards": 10
-        },
         "test": "browser_tests"
       },
       {
@@ -2388,27 +2381,15 @@
         "test": "components_unittests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "content_browsertests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "content_unittests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "courgette_unittests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "crypto_unittests"
       },
       {
@@ -2442,9 +2423,6 @@
         "test": "midi_unittests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "net_unittests"
       },
       {
@@ -2478,9 +2456,6 @@
         "test": "ui_base_unittests"
       },
       {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "unit_tests"
       },
       {