[llvm] [llvm][Support] Call clear_error in LockFileManager to avoid report_fatal_error (PR #83655)

[David Blaikie via llvm-commits]

dwblaikie wrote:

Hmm - this was sent for review but committed without review? 
If you didn't mean for this to require pre-commit review, please add the tag `skip-precommit-approval` when creating the PR (per: https://llvm.org/docs/CodeReview.html#code-review-workflow - though I need to fix the link in the note there... )

As for the change itself - if this code was invoked by a unit test, would it fail the unit test due to report_fatal_error? (or would the unit test exit quietly? I'd think it'd fail) - so maybe could be tested that way? Or is it that it's hard to create the error condition that'd lead to the report fatal error in the first place?

https://github.com/llvm/llvm-project/pull/83655