[llvm] [DWARFVerifier] Fix debug_str_offsets DWARF version detection (PR #81210)

[Felipe de Azevedo Piovezan via llvm-commits]

felipepiovezan wrote:

@dwblaikie I believe you originally added this piece of the verifier. 

We have lots of downstream tests failing because they link "plain old dwarf 4" with dwarf 5, and the verifier is incorrectly interpreting the debug_str_offsets section as DWARF 4, so I'd appreciate it if you could have a look at this.

https://github.com/llvm/llvm-project/pull/81210