[llvm] Minor optimizations to DW_OP_LLVM_extract_bits_* (PR #163812)

[Michael Buch via llvm-commits]

https://github.com/Michael137 commented:

Might be totally off but didnt @rastogishubham and @adrian-prantl  add a Dwarf expression optimizer not too long ago? Could we build this into that?

https://github.com/llvm/llvm-project/pull/163812