[clang] [LifetimeSafety] Add language option for experimental lifetime safety (PR #149592)

[Paul Osmialowski via cfe-commits]

pawosm-arm wrote:

@sjoerdmeijer clang doesn't terminate for me too these days (see #150336) but I tracked it down to PR #144408

https://github.com/llvm/llvm-project/pull/149592