Convert cacheinvalidation_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 51e2394b6b243ad319fc1d32ca5a41848d580981..a0b630eb143fed457e4a4027849cd0f8506a8d16 100644
--- a/testing/buildbot/chromium.mac.json
+++ b/testing/buildbot/chromium.mac.json
@@ -90,6 +90,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {
@@ -262,6 +265,9 @@
         "test": "browser_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {
@@ -491,6 +497,9 @@
         "test": "browser_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {
@@ -714,6 +723,9 @@
         "test": "browser_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {
@@ -937,6 +949,9 @@
         "test": "browser_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {