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

runtime/vm/dart_entry_test.cc

Index: runtime/vm/dart_entry_test.cc
===================================================================
--- runtime/vm/dart_entry_test.cc	(revision 25114)
+++ runtime/vm/dart_entry_test.cc	(working copy)
@@ -28,7 +28,7 @@
   EXPECT_EQ(true, CompilerTest::TestCompileScript(lib, script));
   EXPECT(ClassFinalizer::FinalizePendingClasses());
   Class& cls = Class::Handle(
-      lib.LookupClass(String::Handle(Symbols::New("A"))));
+      lib.LookupClass(String::Handle(Symbols::New("A")), NULL));
   EXPECT(!cls.IsNull());
   String& name = String::Handle(String::New("foo"));
   Function& function = Function::Handle(cls.LookupStaticFunction(name));
@@ -56,7 +56,7 @@
   EXPECT_EQ(true, CompilerTest::TestCompileScript(lib, script));
   EXPECT(ClassFinalizer::FinalizePendingClasses());
   Class& cls = Class::Handle(
-      lib.LookupClass(String::Handle(Symbols::New("A"))));
+      lib.LookupClass(String::Handle(Symbols::New("A")), NULL));
   EXPECT(!cls.IsNull());
   String& name = String::Handle(String::New("foo"));
   Function& function = Function::Handle(cls.LookupStaticFunction(name));
@@ -83,7 +83,7 @@
   EXPECT_EQ(true, CompilerTest::TestCompileScript(lib, script));
   EXPECT(ClassFinalizer::FinalizePendingClasses());
   Class& cls = Class::Handle(
-      lib.LookupClass(String::Handle(Symbols::New("A"))));
+      lib.LookupClass(String::Handle(Symbols::New("A")), NULL));
   EXPECT(!cls.IsNull());
 
   // Invoke the constructor.