chromium: pass proper --src-dir to win_apply_syzyasan.py

scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_win_asan.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "\nimport sys, os\npath = sys.argv[1]\nmode = int(sys.argv[2])\nif not os.path.isdir(path):\n  if os.path.exists(path):\n    print \"%s exists but is not a dir\" % path\n    sys.exit(1)\n  os.makedirs(path, mode)\n",
       "[BUILDER_CACHE]\\win_asan",
       "511"
     ],
     "name": "makedirs checkout path",
@@ skipping 202 matching lines @@
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
       "@@@STEP_LOG_END@json.output (invalid)@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\chromium\\win_apply_syzyasan.py",
+      "--src-dir",
+      "[BUILDER_CACHE]\\win_asan\\src",
       "--target",
       "Release"
     ],
     "name": "apply_syzyasan"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\runtest.py",
@@ skipping 390 matching lines @@
     ],
     "cwd": "[BUILDER_CACHE]\\win_asan",
     "name": "webrtc_nonparallel_tests"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]