[clang] [Clang][analyzer] replace Stmt* with ConstCFGElementRef in SymbolConjured (PR #128251)

[Fangyi Zhou via cfe-commits]

fangyi-zhou wrote:

Looks like there's an Asan issue at the stale CFG element for loop widening https://lab.llvm.org/buildbot/#/builders/55/builds/10398. Do we need to revert?

https://github.com/llvm/llvm-project/pull/128251