[core] Fix improper name normalization in KeepNParams

[silverweed]

The algorithm was not recording any default arguments into argsToKeep, but it actually needs to keep them as long as they are followed by a non-default argument.

This would cause issues such as this:

// std::less<int> is a default argument, but MyAlloc is not 
using MyMap = std::map<int, int, std::less<int>, MyAlloc>;

TClass::GetClass("MyMap")->GetName() // prints "map<int,int,MyAlloc>" !

NOTE

I am not familiar with the Cling codebase so this fix might be missing something or be wrong for some other reason. The TClassEdit tests are passing, at least, but I kindly ask Cling experts to scrutinize this change thoroughly.

Checklist:

• tested changes locally
• updated the docs (if necessary)

This PR fixes #

[github-actions]

Test Results

    22 files      22 suites   3d 5h 47m 44s ⏱️
 3 807 tests  3 804 ✅ 1 💤 2 ❌
76 698 runs  76 684 ✅ 9 💤 5 ❌

For more details on these failures, see this check.

Results for commit f4e0d07.

♻️ This comment has been updated with latest results.

[silverweed]

Test fails on mac with:

2026-03-11T17:37:05.5216310Z Expected equality of these values:
2026-03-11T17:37:05.5219690Z   "std::map<int,int>"
2026-03-11T17:37:05.5219810Z   n.c_str()
2026-03-11T17:37:05.5220220Z     Which is: "map<int,int>"

which is concerning...