Clean up some GN/hermetic build changes.

build/toolchain/toolchain.gni

Index: build/toolchain/toolchain.gni
diff --git a/build/toolchain/toolchain.gni b/build/toolchain/toolchain.gni
index dab5b77c7c9f8d6ef820acdadbce9ad71f6d222b..678b91ac84ff75045bd768ceed0b47885d9b7064 100644
--- a/build/toolchain/toolchain.gni
+++ b/build/toolchain/toolchain.gni
@@ -47,13 +47,13 @@ declare_args() {
   # obtained with gclient sync after setting the environment variable
   # FORCE_MAC_TOOLCHAIN].
   use_system_xcode = true
-
-  # The path to the hermetic install of Xcode. Only relevant when
-  # use_system_xcode = false.
-  hermetic_xcode_path =
-      rebase_path("//build/mac_files/Xcode.app", "", root_build_dir)
 }
 
+# The path to the hermetic install of Xcode. Only relevant when
+# use_system_xcode = false.
+hermetic_xcode_path =
+    rebase_path("//build/mac_files/Xcode.app", "", root_build_dir)
+
 declare_args() {
   if (is_clang) {
     # Clang compiler version. Clang files are placed at version-dependent paths.