[clang] [LifetimeSafety] Add bailout for large CFGs (PR #170444)

[Utkarsh Saxena via cfe-commits]

================
@@ -1964,6 +1964,14 @@ defm lifetime_safety : BoolFOption<
   BothFlags<[], [CC1Option],
           " experimental lifetime safety for C++">>;
 
+def fexperimental_lifetime_safety_max_cfg_blocks
----------------
usx95 wrote:

nit: drop the prefix and rename to `lifetime_safety_max_cfg_blocks`

https://github.com/llvm/llvm-project/pull/170444