Mark flaky gm as ignore-failure on mac 10.9

expectations/gm/Test-Mac10.9-MacMini6.2-HD4000-x86_64-Debug/expected-results.json

 {
   "actual-results": {
     "failed": null, 
     "failure-ignored": null, 
     "no-comparison": null, 
     "succeeded": null
   }, 
   "expected-results": {
     "3x3bitmaprect_565.png": {
       "allowed-digests": [
@@ skipping 5175 matching lines @@
           "bitmap-64bitMD5", 
           12796163724344544719
         ]
       ], 
       "reviewed-by-human": true
     }, 
     "complexclip2_path_aa_gpu.png": {
       "allowed-digests": [
         [
           "bitmap-64bitMD5", 
-          16801220727816566913
+          3563196831027840490
         ]
       ], 
+      "bugs": [
+        3256
+      ], 
+      "ignore-failure": true, 
       "reviewed-by-human": true
     }, 
     "complexclip2_path_aa_pdf-mac.png": {
       "allowed-digests": [
         [
           "bitmap-64bitMD5", 
           14487671086018162616
         ]
       ], 
       "reviewed-by-human": true
@@ skipping 12636 matching lines @@
       "allowed-digests": [
         [
           "bitmap-64bitMD5", 
           12937422788648264516
         ]
       ], 
       "reviewed-by-human": true
     }
   }
 }