[clang] Evaluate non-type default template argument when it is required

Before this change a default template argument for a non-type template
parameter was evaluated and checked immediately after it is met by
parser. In some cases it is too early.

Fixes https://github.com/llvm/llvm-project/issues/62224
Fixes https://github.com/llvm/llvm-project/issues/62596

Reviewed By: shafik, erichkeane, cor3ntin

Differential Revision: https://reviews.llvm.org/D150108