[core] Difference in `typedef`/`using` resolution in Windows and Linux builds

[jalopezg-git]

Describe the bug

As seen as part of #12657 (which fixed an issue on Windows builds), TClassEdit::ResolveTypedef() returns different results in Windows and Linux builds. This should be investigated.

The issue can be easily reproduced: a Linux build does not resolve the using type alias, as seen below

root [0] TClassEdit::ResolveTypedef("ROOT::Experimental::ClusterSize_t")
(std::string) "ROOT::Experimental::ClusterSize_t"

whereas a Windows build, for some reason does,

root [0] TClassEdit::ResolveTypedef("ROOT::Experimental::ClusterSize_t")
(std::string) "ROOT::Experimental::RClusterSize"

Expected behavior

Both builds should be probably resolving the using declaration.

Setup

1. ROOT version: master
2. Operating system: Archlinux x86_64 (GNU/Linux), and Microsoft Windows x86_64 built from the master branch

Additional context

ROOT::Experimental::ClusterSize_t is an alias of type ROOT::Experimental::RClusterSize (see https://github.com/root-project/root/blob/master/tree/ntuple/v7/inc/ROOT/RNTupleUtil.hxx#L63)