[llvm] [Dwarf] Emit `DW_AT_bit_size` for non-byte-sized types (PR #137118)

[David Blaikie via llvm-commits]

dwblaikie wrote:

Yeah, not sure we should create `DW_OP_LLVM_convert, 1` and if we do, not sure we should lower it to an integer of size 1... doesn't seem likely to be what most consumers would expect?

https://github.com/llvm/llvm-project/pull/137118