[Release] CC hpayer@ and ulan@ to every heap change

NOTRY=true
TBR=hpayer@chromium.org, ulan@chromium.org

Review URL: https://codereview.chromium.org/1490263002

Cr-Commit-Position: refs/heads/master@{#32510}

WATCHLISTS

@@ -50,6 +50,9 @@
     'feature_shipping_status': {
       'filepath': 'src/flag-definitions.h',
     },
+    'gc_changes': {
+      'filepath': 'src/heap/',
+    },
   },
 
   'WATCHLISTS': {
@@ -69,5 +72,9 @@
     'feature_shipping_status': [
       'hablich@chromium.org',
     ],
+    'gc_changes': [
+      'hpayer@chromium.org',
+      'ulan@chromium.org',
+    ],
   },
 }