Implement fails_with_llvm compat method in terms of fails_with

Library/Homebrew/compat/fails_with_llvm.rb

@@ -9,9 +9,7 @@ class Formula
   end
 
   def self.fails_with_llvm msg=nil, data={}
-    case msg when Hash then data = msg end
-    failure = CompilerFailure.new(:llvm) { build(data.delete(:build).to_i) }
-    @cc_failures ||= Set.new
-    @cc_failures << failure
+    data = msg if Hash === msg
+    fails_with(:llvm) { build(data.delete(:build).to_i) }
   end
 end