Disable content_unittests on arm64 fuchsia.fyi bot

SwiftShader is disabled on arm64, so content_unittests fail to
initialize GL and fail.

Bug: 881334
Change-Id: Id84288d0faaff13de6dfd5ca0214ebc2bb5ce062
Reviewed-on: https://chromium-review.googlesource.com/c/1265937Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597653}

testing/buildbot/chromium.fyi.json

@@ -3244,15 +3244,6 @@
         },
         "test": "base_unittests"
       },
-      {
-        "args": [
-          "--test-launcher-filter-file=../../testing/buildbot/filters/fuchsia.content_unittests.filter"
-        ],
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "content_unittests"
-      },
       {
         "swarming": {
           "can_use_on_swarming_builders": true

testing/buildbot/test_suite_exceptions.pyl

@@ -476,6 +476,10 @@
     },
   },
   'content_unittests': {
+    'remove_from': [
+      # chromium.fyi
+      'fuchsia-fyi-arm64-rel',  # https://crbug.com/881334
+    ],
     'modifications': {
       # chromium.memory
       'Linux ASan LSan Tests (1)': {