Remove content_browsertests from Blimp Linux Engine buildbot recipe.

testing/buildbot/chromium.fyi.json

 {
   "Android Asan Builder Tests (dbg)": {
     "gtest_tests": [
       {
         "args": [
           "--tool=asan"
         ],
         "swarming": {
           "can_use_on_swarming_builders": false
         },
@@ skipping 1209 matching lines @@
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "blimp_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "content_browsertests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "content_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "ipc_tests"
       },
       {
         "swarming": {
@@ skipping 11942 matching lines @@
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "views_unittests"
       }
     ]
   }
 }