Check for a passed-in type argument vector in the prolog of generic functions.

runtime/vm/scopes.h

Index: runtime/vm/scopes.h
diff --git a/runtime/vm/scopes.h b/runtime/vm/scopes.h
index 906603807e636e92f6f036a2b2e20976a298aa27..94a77af35a2b1c548b108a75ea5ee25b883f50fa 100644
--- a/runtime/vm/scopes.h
+++ b/runtime/vm/scopes.h
@@ -314,6 +314,7 @@ class LocalScope : public ZoneAllocated {
   // Return the index of the next available frame slot.
   int AllocateVariables(int first_parameter_index,
                         int num_parameters,
+                        int type_args_slot,
                         int first_frame_index,
                         LocalScope* context_owner,
                         bool* found_captured_variables);