Added GYP defines to dump linux symbols for gpu perf bots and trybots.

scripts/slave/recipes/chromium_trybot.expected/swarming_missing_isolated.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "tryserver.chromium.linux",
       "--builder",
       "linux_chromium_rel_ng",
@@ skipping 69 matching lines @@
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
     "env": {
-      "GYP_DEFINES": "archive_gpu_tests=1 component=static_library dcheck_always_on=1 fastbuild=1 gomadir='[BUILD]/goma' target_arch=x64 test_isolation_mode=prepare use_goma=1"
+      "GYP_DEFINES": "archive_gpu_tests=1 component=static_library dcheck_always_on=1 fastbuild=1 gomadir='[BUILD]/goma' linux_dump_symbols=1 target_arch=x64 test_isolation_mode=prepare use_goma=1"
     },
     "name": "gclient runhooks (with patch)"
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/src/testing/buildbot/chromium.linux.json",
       "/path/to/tmp/json"
@@ skipping 1768 matching lines @@
       "https://chromium-swarm.appspot.com",
       "--decorate",
       "--print-status-updates",
       "--shards",
       "1",
       "tab_capture_end2end_tests on NVIDIA GPU on Linux (with patch)/Linux/[dummy has/linux_chromium_rel_ng/571"
     ],
     "name": "tab_capture_end2end_tests on NVIDIA GPU on Linux (with patch) on Linux"
   }
 ]