Refactor resolution code in the vm to properly handle ambiguity errors.

runtime/vm/intrinsifier_x64.cc

Index: runtime/vm/intrinsifier_x64.cc
===================================================================
--- runtime/vm/intrinsifier_x64.cc	(revision 25291)
+++ runtime/vm/intrinsifier_x64.cc	(working copy)
@@ -1350,8 +1350,8 @@
 bool Intrinsifier::Random_nextState(Assembler* assembler) {
   const Library& math_lib = Library::Handle(Library::MathLibrary());
   ASSERT(!math_lib.IsNull());
-  const Class& random_class =
-      Class::Handle(math_lib.LookupClassAllowPrivate(Symbols::_Random()));
+  const Class& random_class = Class::Handle(
+      math_lib.LookupClassAllowPrivate(Symbols::_Random(), NULL));
   ASSERT(!random_class.IsNull());
   const Field& state_field = Field::ZoneHandle(
       random_class.LookupInstanceField(Symbols::_state()));