[llvm] [debuginfo] Create `--auto-upgrade-llvm-verify-fatal-errors` flag (PR #132115)

[Arthur Eubanks via llvm-commits]

aeubanks wrote:

when autoupgrading bitcode, we want to know if the IR's debug info, potentially from a previous version of LLVM, is compatible with the current version of LLVM's debug info, and strip it if it isn't. the rest of the IR must be autoupgradable, but not debug info. `-disable-auto-upgrade-debug-info` should also do what you want, even if the name is kinda weird for your case. `-disable-auto-upgrade-debug-info` was added to skip this step when we know the input IR is compatible since verification takes a while.

https://github.com/llvm/llvm-project/pull/132115