Ignore a flaky msaa4 GM and some perma-broken S4 GMs

expectations/gm/Test-Ubuntu12-ShuttleA-GTX660-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 14915 matching lines @@
       "bugs": [
         2354
       ], 
       "ignore-failure": true, 
       "reviewed-by-human": true
     }, 
     "mixed_xfermodes_nvprmsaa4.png": {
       "allowed-digests": [
         [
           "bitmap-64bitMD5", 
-          7591469946375994741
+          5471873127527415301
         ]
       ], 
+      "ignore-failure": true, 
       "reviewed-by-human": true
     }, 
     "modecolorfilters_565.png": {
       "allowed-digests": [
         [
           "bitmap-64bitMD5", 
           6489129061840693694
         ]
       ], 
       "reviewed-by-human": true
@@ skipping 7208 matching lines @@
       "allowed-digests": [
         [
           "bitmap-64bitMD5", 
           11835374726311942978
         ]
       ], 
       "reviewed-by-human": true
     }
   }
 }