[Clang] Allow additional mathematical symbols in identifiers.

Implement the proposed UAX Profile
"Mathematical notation profile for default identifiers".

This implements a not-yet approved Unicode for a vetted
UAX31 identifier profile
https://www.unicode.org/L2/L2022/22230-math-profile.pdf

This change mitigates the reported disruption caused
by the implementation of UAX31 in C++ and C2x,
as these mathematical symbols are commonly used in the
scientific community.

Fixes #54732

Reviewed By: tahonermann, #clang-language-wg

Differential Revision: https://reviews.llvm.org/D137051