recipes/win: Stop explicitly disabling precompiled headers in recipes in goma builds.

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 200 matching lines @@
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]\\gclient.py",
       "runhooks"
     ],
     "cwd": "[BUILDER_CACHE]\\win_chromium_rel_ng\\src",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json",
       "GYP_CHROMIUM_NO_ACTION": "1",
-      "GYP_DEFINES": "archive_gpu_tests=1 chromium_win_pch=0 component=static_library dcheck_always_on=1 fastbuild=1 ffmpeg_branding=Chrome gomadir='[CACHE]\\cipd\\goma' proprietary_codecs=1 target_arch=ia32 test_isolation_mode=prepare use_goma=1",
+      "GYP_DEFINES": "archive_gpu_tests=1 component=static_library dcheck_always_on=1 fastbuild=1 ffmpeg_branding=Chrome gomadir='[CACHE]\\cipd\\goma' proprietary_codecs=1 target_arch=ia32 test_isolation_mode=prepare use_goma=1",
       "PATH": "%(PATH)s;RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "gclient runhooks (with patch)",
     "~followup_annotations": [
       "step returned non-zero exit code: 1",
       "@@@STEP_FAILURE@@@"
     ]
   },
   {
     "cmd": [
@@ skipping 100 matching lines @@
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]\\gclient.py",
       "runhooks"
     ],
     "cwd": "[BUILDER_CACHE]\\win_chromium_rel_ng\\src",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json",
       "GYP_CHROMIUM_NO_ACTION": "1",
-      "GYP_DEFINES": "archive_gpu_tests=1 chromium_win_pch=0 component=static_library dcheck_always_on=1 fastbuild=1 ffmpeg_branding=Chrome gomadir='[CACHE]\\cipd\\goma' proprietary_codecs=1 target_arch=ia32 test_isolation_mode=prepare use_goma=1",
+      "GYP_DEFINES": "archive_gpu_tests=1 component=static_library dcheck_always_on=1 fastbuild=1 ffmpeg_branding=Chrome gomadir='[CACHE]\\cipd\\goma' proprietary_codecs=1 target_arch=ia32 test_isolation_mode=prepare use_goma=1",
       "PATH": "%(PATH)s;RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "gclient runhooks (without patch)",
     "~followup_annotations": [
       "step returned non-zero exit code: 1",
       "@@@STEP_FAILURE@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "import sys; sys.exit(0)"
     ],
     "name": "mark: before_tests",
     "~followup_annotations": [
       "@@@SET_BUILD_PROPERTY@failure_hash@\"c18cfb87382155d691c887ecad8e8bf7cdf0fab3\"@@@"
     ]
   },
   {
     "name": "$result",
     "reason": "Step('gclient runhooks (without patch)') failed with return_code 1",
     "recipe_result": null,
     "status_code": 1
   }
 ]