[lld] [llvm] [LLVM] Use `reportFatalUsageError` for LTO usage errors (PR #140955)

[via llvm-commits]

bd1976bris wrote:

Digging into why the [lto-cache-errors.ll](https://github.com/llvm/llvm-project/blob/e165bea1d4ec2de96ee0548cece79d71a75ce8f8/lld/test/COFF/lto-cache-errors.ll) test fails non-deterministically, I suspect that `reportFatalUsageError` can cause a crash if threads call `reportFatalUsageError` simultaneously (the ThinLTO cache dir is used from a multi-threaded context). I have observed this on Linux. It may also apply on Windows. This will need to be solved before we can use `reportFatalUsageError` for these errors. I don't have the time to work on this right now so I have unassigned myself from https://github.com/llvm/llvm-project/issues/140953 so that someone else can pick this up if they are interested. I am hopeful that I can land the other piece of this though: #140956.

https://github.com/llvm/llvm-project/pull/140955