[clang] [clang-analysis]Fix false positive in mutation check when using pointer to member function (PR #66846)

[Congcong Cai via cfe-commits]

================
@@ -274,8 +288,8 @@ const Stmt *ExprMutationAnalyzer::findDirectMutation(const Expr *Exp) {
   const auto NonConstMethod = cxxMethodDecl(unless(isConst()));
 
   const auto AsNonConstThis = expr(anyOf(
-      cxxMemberCallExpr(callee(NonConstMethod),
-                        on(canResolveToExpr(equalsNode(Exp)))),
+      cxxMemberCallExpr(on(canResolveToExpr(equalsNode(Exp))),
+                        unless(isConstCallee())),
----------------
HerrCai0907 wrote:

see this test case

```c++
buildASTFromCode("struct X {};"
                 "using T = int (X::*)() const;"
                 "void f(X &x, T m) { X &ref = x; (ref.*m)(); }");
```

https://github.com/llvm/llvm-project/pull/66846