[clang] [clang] handle fp options in __builtin_convertvector (PR #125522)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

1 nit, otherwise no real concerns.  I don't know enough about this feature to be great at reviewing, and the nit might be just a fallout from what we already have, but otherwise it seems reasonable enough to me.

Glad to see we have a ast-dump test that seems to have tests for serialization, though wouldn't mind a little bit more of a 'small test' on it to ensure we are printing everything.

https://github.com/llvm/llvm-project/pull/125522