[clang] [LifetimeSafety] Support C Language in LifetimeSafety (PR #203270)

[Utkarsh Saxena via cfe-commits]

usx95 wrote:

Let us do this behind an experimental flag in this PR itself. In a subsequent PR, we can default the value of the flag to true along with release notes + lifetime safety docs. If widespread crashes are reported, it is easier to rollback that particular change. Once stable enough (say after a few weeks), we can remove the flag.

https://github.com/llvm/llvm-project/pull/203270