Revert my last change due to problems on other platforms.

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
===================================================================
--- runtime/vm/compiler.cc	(revision 6128)
+++ runtime/vm/compiler.cc	(working copy)
@@ -111,14 +111,6 @@
 
 static RawError* CompileFunctionHelper(const Function& function,
                                        bool optimized) {
-  if (function.is_compiling()) {
-    ASSERT(function.is_const() && function.IsConstructor());
-    const String& msg = String::Handle(String::NewFormatted(
-        "Illegal recursion in const constructor '%s'.",
-        String::Handle(function.name()).ToCString()));
-    return LanguageError::New(msg);
-  }
-  function.set_is_compiling(true);
   Isolate* isolate = Isolate::Current();
   Error& error = Error::Handle();
   LongJump* base = isolate->long_jump_base();
@@ -311,7 +303,6 @@
     isolate->object_store()->clear_sticky_error();
   }
   isolate->set_long_jump_base(base);
-  function.set_is_compiling(false);
   return error.raw();
 }