on CompareGMs failure, show link to most recent results on this builder

site_config/global_variables.json

 {
   "android_external_port": {
     "value": "10117",
     "type": "integer",
     "description": "Externally-visible port on the Android Skia build master."
   },
   "android_internal_port": {
     "value": "10115",
     "type": "integer",
     "description": "Internally-visible port on the Android Skia build master."
@@ skipping 178 matching lines @@
   "gm_summaries_bucket": {
     "value": "chromium-skia-gm-summaries",
     "type": "string",
     "description": "Google Cloud Storage bucket we use for GM actual-result.json files."
   },
   "googlestorage_bucket": {
     "value": "gs://chromium-skia-gm",
     "type": "string",
     "description": "Google Cloud Storage bucket we use for most things."
   },
+  "latest_gm_failures_preamble": {
+    "value": "View latest GM failures for this builder at: ",
+    "type": "string",
+    "description": "Wording that leads up to URL pointing at latest GM results for this builder."
+  },
   "master_branch_name": {
     "value": "master",
     "type": "string",
     "description": "The git branch on which the bots operate."
   },
   "num_gce_compile_bots": {
     "value": "5",
     "type": "integer",
     "description": "The number of Compile buildbots on GCE."
   },
@@ skipping 91 matching lines @@
     "value": "https://skia-tree-status.appspot.com/binary-status",
     "type": "string",
     "description": "URL that displays the status of the Skia tree."
   },
   "try_svn_url": {
     "value": "http://skia-try.googlecode.com/svn",
     "type": "string",
     "description": "URL of the SVN repository used for try requests."
   }
 }