Convert blink_heap_unittests to run exclusively on Swarming

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 fcabc695289ee633af69c76bb24be384479cf996..d1be4e96aae7b90300213be5d52d41c5b8f8b4ff 100644
--- a/testing/buildbot/chromium.fyi.json
+++ b/testing/buildbot/chromium.fyi.json
@@ -657,6 +657,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -859,6 +862,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -1017,6 +1023,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -1219,6 +1228,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -1407,6 +1419,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -1559,6 +1574,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -1711,6 +1729,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -1863,6 +1884,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -2015,6 +2039,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -2167,6 +2194,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -2901,6 +2931,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -3053,6 +3086,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -3205,6 +3241,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -3357,6 +3396,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -3506,6 +3548,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -3636,6 +3681,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {
@@ -3788,6 +3836,9 @@
         "test": "base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "blink_heap_unittests"
       },
       {