Do not require type class to be finalized when performing a type test.

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 6439)
+++ runtime/vm/object.cc	(working copy)
@@ -1490,13 +1490,16 @@
 }
 
 
+// Checks if the type S is a subtype of type T.
+// Type S is specified by this class parameterized with 'type_arguments', and
+// type T by class 'other' parameterized with 'other_type_arguments'.
+// This class and class 'other' do not need to be finalized, however, they must
+// be resolved as well as their interfaces.
 bool Class::IsSubtypeOf(
     const AbstractTypeArguments& type_arguments,
     const Class& other,
     const AbstractTypeArguments& other_type_arguments,
     Error* malformed_error) const {
-  ASSERT(is_finalized());
-  ASSERT(other.is_finalized());
   // Check for DynamicType.
   // The DynamicType on the lefthand side is replaced by the bottom type, which
   // is more specific than any type.