[clang] [llvm] [SystemZ, Clang] Enable verification of int args extensions by default. (PR #223755)

[Jonas Paulsson via cfe-commits]

JonPsson1 wrote:

It seems that csmith testing has also run now for some time without any findings.

IBM Bob however discovered a few more places of missing extensions:
- https://github.com/llvm/llvm-project/pull/232128
- https://github.com/llvm/llvm-project/pull/232581
- https://github.com/llvm/llvm-project/pull/232600

https://github.com/llvm/llvm-project/pull/223755