dev-cmd/prof: bleed less of the environment from gem installs

Library/Homebrew/dev-cmd/prof.rb

@@ -22,7 +22,7 @@ module Homebrew
   def prof
     args = prof_args.parse
 
-    Homebrew.install_bundler_gems!(groups: ["prof"])
+    Homebrew.install_bundler_gems!(groups: ["prof"], setup_path: false)
 
     brew_rb = (HOMEBREW_LIBRARY_PATH/"brew.rb").resolved_path
     FileUtils.mkdir_p "prof"
@@ -40,6 +40,8 @@ module Homebrew
       raise UsageError, "`#{cmd}` is an unknown command!"
     end
 
+    Homebrew.setup_gem_environment!
+
     if args.stackprof?
       with_env HOMEBREW_STACKPROF: "1" do
         system(*HOMEBREW_RUBY_EXEC_ARGS, brew_rb, *args.named)