[clang] [clang] Remove fixed point arithmetic error (PR #71884)

[John McCall via cfe-commits]

rjmccall wrote:

I definitely don't think we should be handling this in the lexer by trying to retroactively make this a keyword. I was just thinking that we might have some sort of parser-level recovery for e.g. `unrecognized_identifier_t x = 5;` that might guess that `unrecognized_identifier_t` is a type name, and it would be reasonable for that to special-case type names that aren't keywords in the current language settings.  But if we don't have that recovery already, we don't have it, and I'm not going to ask you to add it just for this patch.

https://github.com/llvm/llvm-project/pull/71884