Remove parent_level field of function type parameters.

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
diff --git a/runtime/vm/intermediate_language.cc b/runtime/vm/intermediate_language.cc
index 894d7fa7912055d89f517c2c9b7cee6f83200f47..002d6dfffde83e78819d1c3fb3ab8c2dfdcd63be 100644
--- a/runtime/vm/intermediate_language.cc
+++ b/runtime/vm/intermediate_language.cc
@@ -2064,16 +2064,11 @@ Definition* AssertAssignableInstr::Canonicalize(FlowGraph* flow_graph) {
       value()->Type()->IsAssignableTo(dst_type())) {
     return value()->definition();
   }
-
-  // For uninstantiated target types: If the instantiator and function
-  // type arguments are constant, instantiate the target type here.
-  // If the uninstantiated type refers to parent function type parameters, we
-  // cannot instantiated it here.
-  if (dst_type().IsInstantiated() ||
-      !dst_type().IsInstantiated(kParentFunctions)) {
+  if (dst_type().IsInstantiated()) {
     return this;
   }
-
+  // For uninstantiated target types: If the instantiator and function
+  // type arguments are constant, instantiate the target type here.
   ConstantInstr* constant_instantiator_type_args =
       instantiator_type_arguments()->definition()->AsConstant();
   ConstantInstr* constant_function_type_args =