Added gl_unittests to various try/build bots.

testing/buildbot/tryserver.chromium.linux.json

 {
   "android_chromium_gn_compile_dbg": {
     "additional_compile_targets": [
       "chrome_shell_apk"
     ],
     "gtest_tests": []
   },
   "android_chromium_gn_compile_rel": {
     "additional_compile_targets": [
       "chrome_shell_apk"
@@ skipping 117 matching lines @@
       "content_unittests",
       "crypto_unittests",
       "dbus_unittests",
       "device_unittests",
       "display_unittests",
       "events_unittests",
       "extensions_browsertests",
       "extensions_unittests",
       "gcm_unit_tests",
       "gfx_unittests",
+      "gl_unittests",
       "gn_unittests",
       "google_apis_unittests",
       "gpu_unittests",
       "interactive_ui_tests",
       "ipc_mojo_unittests",
       "ipc_tests",
       "jingle_unittests",
       "mandoline:all",
       "media_unittests",
       "net_unittests",
@@ skipping 85 matching lines @@
       {
         "test": "extensions_unittests"
       },
       {
         "test": "gcm_unit_tests"
       },
       {
         "test": "gfx_unittests"
       },
       {
+        "test": "gl_unittests"
+      },
+      {
         "test": "gn_unittests"
       },
       {
         "test": "google_apis_unittests"
       },
       {
         "test": "gpu_unittests"
       },
       {
         "test": "ipc_mojo_unittests"
@@ skipping 39 matching lines @@
       },
       {
         "test": "views_unittests"
       },
       {
         "test": "wm_unittests"
       }
     ]
   }
 }