[clang] [clang] Update argument checking tablegen code to use a 'full' name (PR #99993)

[Mike Rice via cfe-commits]

mikerice1969 wrote:

> You probably need to separately match the syntax and the name without constructing a temporary `std::string`.

@nikic Thanks. I'll look into improving this. If anyone thinks this should be reverted until then let me know, or just go ahead and revert it.

https://github.com/llvm/llvm-project/pull/99993