Convert sql_unittests to run exclusively on Swarming

testing/buildbot/chromium.mac.json

Index: testing/buildbot/chromium.mac.json
diff --git a/testing/buildbot/chromium.mac.json b/testing/buildbot/chromium.mac.json
index a0b630eb143fed457e4a4027849cd0f8506a8d16..fc72df886088e3672962211bcf44f2587f784ef2 100644
--- a/testing/buildbot/chromium.mac.json
+++ b/testing/buildbot/chromium.mac.json
@@ -204,6 +204,9 @@
         "test": "skia_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {
@@ -424,6 +427,9 @@
         "test": "skia_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {
@@ -650,6 +656,9 @@
         "test": "skia_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {
@@ -876,6 +885,9 @@
         "test": "skia_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {
@@ -1103,6 +1115,9 @@
         "test": "skia_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {