Convert cacheinvalidation_unittests to run exclusively on Swarming

testing/buildbot/chromium.linux.json

Index: testing/buildbot/chromium.linux.json
diff --git a/testing/buildbot/chromium.linux.json b/testing/buildbot/chromium.linux.json
index 49526391a6ba1cd80e01df8e24d1de4257dd72fa..95ad1b27bea4c420f0ab6aff7c6b7e083d591af8 100644
--- a/testing/buildbot/chromium.linux.json
+++ b/testing/buildbot/chromium.linux.json
@@ -100,6 +100,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {
@@ -493,6 +496,9 @@
         "test": "browser_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {
@@ -779,6 +785,9 @@
         "test": "browser_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {
@@ -1051,6 +1060,9 @@
         "test": "browser_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "cacheinvalidation_unittests"
       },
       {