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

scripts/slave/recipes/findit/chromium/test.expected/compile_skipped.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 171 matching lines @@
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]\\gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]\\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 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 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"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]\\src\\testing\\scripts\\get_compile_targets.py",
       "--output",
@@ skipping 231 matching lines @@
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]\\gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]\\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 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 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": "test r1.gclient runhooks",
     "~followup_annotations": [
       "@@@STEP_NEST_LEVEL@1@@@"
     ]
   },
   {
     "cmd": [
       "python",
@@ skipping 111 matching lines @@
       "@@@STEP_LOG_END@report@@@",
       "@@@SET_BUILD_PROPERTY@report@{\"metadata\": {\"regression_range_size\": 1}, \"result\": {\"r1\": {\"checkperms\": {\"status\": \"passed\", \"valid\": true}}}}@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]