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

scripts/slave/recipes/gpu/build_and_test.expected/linux_debug.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/cleanup_temp.py"
     ],
     "name": "cleanup temp"
   },
   {
@@ skipping 59 matching lines @@
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
     "env": {
-      "GYP_DEFINES": "archive_gpu_tests=1 blink_logging_always_on=1 component=shared_library dcheck_always_on=1 disable_glibcxx_debug=1 ffmpeg_branding=Chrome gomadir='[BUILD]/goma' internal_gles2_conform_tests=1 proprietary_codecs=1 target_arch=x64 test_isolation_mode=prepare use_goma=1"
+      "GYP_DEFINES": "archive_gpu_tests=1 blink_logging_always_on=1 component=shared_library dcheck_always_on=1 disable_glibcxx_debug=1 ffmpeg_branding=Chrome gomadir='[BUILD]/goma' internal_gles2_conform_tests=1 linux_dump_symbols=1 proprietary_codecs=1 target_arch=x64 test_isolation_mode=prepare use_goma=1"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[isolate]/resources/find_isolated_tests.py",
       "--build-dir",
       "[SLAVE_BUILD]/src/out/Debug",
@@ skipping 680 matching lines @@
     ],
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
     "name": "gpu_rasterization_tests",
     "~followup_annotations": [
       "@@@STEP_TEXT@<br/>failures:<br/>Test.Test1<br/>@@@"
     ]
   }
 ]