[llvm] [AArch64TargetParser]Fix reconstructFromParsedFeatures ignoring negative features (PR #142236)

[Tomas Matheson via llvm-commits]

https://github.com/tmatheson-arm commented:

Since `reconstructFromParsedFeatures` is intended to reconstruct the extensions bitset from the `-cc1` command line, I'd like to see an integration test in addition to the TargetParserTests unittest. For example using `-cc1` with `--print-enabled-extensions` if that is possible.

https://github.com/llvm/llvm-project/pull/142236