Revert of Download the hermetic xcode toolchain on all bots that target mac.

scripts/slave/recipes/chromium.expected/full_chromium_lkgr_Mac_ASAN_Release_Media.json

Index: scripts/slave/recipes/chromium.expected/full_chromium_lkgr_Mac_ASAN_Release_Media.json
diff --git a/scripts/slave/recipes/chromium.expected/full_chromium_lkgr_Mac_ASAN_Release_Media.json b/scripts/slave/recipes/chromium.expected/full_chromium_lkgr_Mac_ASAN_Release_Media.json
index c333d6a6d6edb42204a8f116d91549ed5831c48d..20a677b28865ad3cec381a55d22016a12fbc7490 100644
--- a/scripts/slave/recipes/chromium.expected/full_chromium_lkgr_Mac_ASAN_Release_Media.json
+++ b/scripts/slave/recipes/chromium.expected/full_chromium_lkgr_Mac_ASAN_Release_Media.json
@@ -206,7 +206,6 @@
     ],
     "cwd": "[BUILDER_CACHE]/Mac_ASAN_Release_Media/src",
     "env": {
-      "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json",
       "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_DEFINES": "asan=1 clang=1 component=static_library enable_ipc_fuzzer=1 fastbuild=0 ffmpeg_branding=Chrome gomadir='[CACHE]/cipd/goma' host_arch=x64 proprietary_codecs=1 target_arch=x64 use_goma=1 v8_enable_verify_heap=1",
@@ -243,7 +242,6 @@
     ],
     "cwd": "[BUILDER_CACHE]/Mac_ASAN_Release_Media/src",
     "env": {
-      "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "generate_build_files"
@@ -260,7 +258,6 @@
       "/path/to/tmp/json"
     ],
     "env": {
-      "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "clang_revision",
@@ -311,7 +308,6 @@
       "chromium_builder_asan"
     ],
     "env": {
-      "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "compile",