Add type adapter to type.thrift
Add type adapter to type.thrift

Summary: thrift/any stores type as TypeStruct. We need an adapter to change TypeStruct to `IThriftStruct::TGenericSpec`, a shape that has all the info needed for deserialization

Reviewed By: kvchen

Differential Revision: D39962659

fbshipit-source-id: 0ba940adfaea2418aef0ec9a09ef33c85ac3c1e9

facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift