Stop running content_unittests on Chromium recipe GPU FYI bots.

It looks like it's killing the bots.

BUG=542370, 573599
TBR=maruel@chromium.org, vadimsh@chromium.org, watk@chromium.org, dalecurtis@chromium.org
NOTRY=true
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/1557783002

Cr-Commit-Position: refs/heads/master@{#367274}

testing/buildbot/chromium.gpu.fyi.json

@@ -65,18 +65,6 @@
         },
         "test": "content_gl_tests"
       },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "dimension_sets": [
-            {
-              "gpu": "10de:104a",
-              "os": "Linux"
-            }
-          ]
-        },
-        "test": "content_unittests"
-      },
       {
         "args": [
           "--use-gpu-in-tests"
@@ -418,18 +406,6 @@
         },
         "test": "content_gl_tests"
       },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "dimension_sets": [
-            {
-              "gpu": "10de:104a",
-              "os": "Linux"
-            }
-          ]
-        },
-        "test": "content_unittests"
-      },
       {
         "args": [
           "--use-gpu-in-tests"