Remove Linux ChromiumOS GN build configs from //testing/buildbot.

testing/buildbot/chromium.chromiumos.json

Index: testing/buildbot/chromium.chromiumos.json
diff --git a/testing/buildbot/chromium.chromiumos.json b/testing/buildbot/chromium.chromiumos.json
index a7e86aa8d64ab88af5f98203f9823a164886948d..1ee55f47de27aab1bf6c33f996cfe71676505d34 100644
--- a/testing/buildbot/chromium.chromiumos.json
+++ b/testing/buildbot/chromium.chromiumos.json
@@ -4,62 +4,6 @@
       "All"
     ]
   },
-  "Linux ChromiumOS GN": {
-    "additional_compile_targets": [
-      "gn_all"
-    ],
-    "gtest_tests": [
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "base_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "exo_unittests"
-      },
-      {
-        "args": [
-          "--override-use-gl-with-osmesa-for-tests"
-        ],
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "mash_unittests"
-      }
-    ]
-  },
-  "Linux ChromiumOS GN (dbg)": {
-    "additional_compile_targets": [
-      "gn_all"
-    ],
-    "gtest_tests": [
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "base_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "exo_unittests"
-      },
-      {
-        "args": [
-          "--override-use-gl-with-osmesa-for-tests"
-        ],
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "mash_unittests"
-      }
-    ]
-  },
   "Linux ChromiumOS Ozone Tests (1)": {
     "gtest_tests": [
       {