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

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

Index: scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_mac_asan.json
diff --git a/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_mac_asan.json b/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_mac_asan.json
index e9927926fcd8d6e88dfc4b2e081b96a4834e43c2..01d430e44de813cc2597e28bfad0a9ddebe99f4e 100644
--- a/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_mac_asan.json
+++ b/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_mac_asan.json
@@ -181,7 +181,6 @@
     ],
     "cwd": "[BUILDER_CACHE]/Mac_Asan/src",
     "env": {
-      "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json",
       "GYP_DEFINES": "asan=1 clang=1 component=static_library dcheck_always_on=1 fastbuild=0 ffmpeg_branding=Chrome gomadir='[CACHE]/cipd/goma' lsan=1 rtc_use_h264=1 target_arch=x64 use_goma=1",
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
@@ -207,7 +206,6 @@
     ],
     "cwd": "[BUILDER_CACHE]/Mac_Asan/src",
     "env": {
-      "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "generate_build_files"
@@ -224,7 +222,6 @@
       "/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",
@@ -272,7 +269,6 @@
       "--"
     ],
     "env": {
-      "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "compile",