Add read only handles for the following predefined symbols

vm/object.cc

Index: vm/object.cc
===================================================================
--- vm/object.cc	(revision 15918)
+++ vm/object.cc	(working copy)
@@ -1250,6 +1250,11 @@
 };
 
 
+bool Object::IsPredefinedHandle() const {
+  return Symbols::IsPredefinedHandle(reinterpret_cast<uword>(this));
+}
+
+
 RawObject* Object::Clone(const Object& src, Heap::Space space) {
   const Class& cls = Class::Handle(src.clazz());
   intptr_t size = src.raw()->Size();
@@ -3395,10 +3400,9 @@
 
 bool Function::IsInlineable() const {
   // '==' call is handled specially.
-  const String& equality_name = String::Handle(Symbols::EqualOperator());
   return InlinableBit::decode(raw_ptr()->kind_tag_) &&
          HasCode() &&
-         name() != equality_name.raw();
+         name() != Symbols::EqualOperator();
 }