Remove parent_level field of function type parameters.

runtime/vm/raw_object_snapshot.cc

Index: runtime/vm/raw_object_snapshot.cc
diff --git a/runtime/vm/raw_object_snapshot.cc b/runtime/vm/raw_object_snapshot.cc
index 7e823b75b222279306eb1d79772ede372273a827..0168374f2b649b776cd0d12787eb0ce57e882781 100644
--- a/runtime/vm/raw_object_snapshot.cc
+++ b/runtime/vm/raw_object_snapshot.cc
@@ -340,7 +340,6 @@ RawTypeParameter* TypeParameter::ReadFrom(SnapshotReader* reader,
   type_parameter.set_token_pos(
       TokenPosition::SnapshotDecode(reader->Read<int32_t>()));
   type_parameter.set_index(reader->Read<int16_t>());
-  type_parameter.set_parent_level(reader->Read<uint8_t>());
   type_parameter.set_type_state(reader->Read<int8_t>());
 
   // Set all the object fields.
@@ -375,7 +374,6 @@ void RawTypeParameter::WriteTo(SnapshotWriter* writer,
   // Write out all the non object pointer fields.
   writer->Write<int32_t>(ptr()->token_pos_.SnapshotEncode());
   writer->Write<int16_t>(ptr()->index_);
-  writer->Write<uint8_t>(ptr()->parent_level_);
   writer->Write<int8_t>(ptr()->type_state_);
 
   // Write out all the object pointer fields.