[clang] [clang][bytecode] Start implementing __builtin_bit_cast (PR #112126)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

Implementation seems reasonable to me, a couple of nits (and please make more detailed asserts for everything!), though I haven't paid attention to these reviews in long enough someone else should take a look.

https://github.com/llvm/llvm-project/pull/112126