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

[via cfe-commits]

================
@@ -1515,7 +1515,8 @@ void CStringChecker::evalCopyCommon(CheckerContext &C, const CallEvent &Call,
       // conjure a return value for later.
       if (lastElement.isUnknown())
         lastElement = C.getSValBuilder().conjureSymbolVal(
-            nullptr, Call.getOriginExpr(), LCtx, C.blockCount());
+            nullptr, Call.getCFGElementRef(), LCtx,
+            Call.getOriginExpr()->getType(), C.blockCount());
----------------
isuckatcs wrote:

```suggestion
            Call.getOriginExpr()->getType(), C.blockCount());
```
`Call.getOriginExpr()` can return null, in which case we crash.

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