[clang] Remove type-punning in LazyOffsetPtr. (PR #112806)

[Richard Smith via cfe-commits]

zygoloid wrote:

> > This violates aliasing rules and doesn't work at all on big-endian 64-bit systems where the pointer is stored in the second four bytes of the uint64_t.
> 
> Your sizes aren't correct in the description here. This issue occurs on big endian 32-bit systems,

Yeah, sorry, just a typo. Fixed.

https://github.com/llvm/llvm-project/pull/112806