Rename all 'WebKit Linux' builders to 'WebKit Linux Precise' (1/3 CLs)

scripts/slave/gatekeeper.json

 {
   "comment": ["This is a configuration file for gatekeeper_ng.py",
               "Look at that for documentation on this file's format."],
 
   "masters": {
     "https://build.chromium.org/p/chromium": [
       {
         "categories": [
           "chromium_tree_closer"
         ],
@@ skipping 743 matching lines @@
             "tree_notify": [
               "machenbach@chromium.org",
               "hablich@chromium.org"
             ],
             "forgive_all": "true",
             "closing_optional": [
               "compile"
             ],
             "subject_template": "V8 API checker %(result)s in %(project_name)s, revision %(revision)s"
           },
-          "WebKit Linux - TraceWrappables": {
+          "WebKit Linux Precise - TraceWrappables": {
             "tree_notify": [
               "hlopko@chromium.org"
             ],
             "forgive_all": "true",
             "closing_optional": [
               "webkit_tests"
             ]
           },
           "Site Isolation Linux": {
             "tree_notify": [
@@ skipping 232 matching lines @@
         "cleanup_temp",
         "taskkill"
       ],
       "closing_optional": [
         "compile",
         "gn"
       ]
     }
   }
 }