[clang] [NFC][analyzer] Cleanup checker calls in `ExprEngine::ProcessStmt`, `ExprEngine::Visit*` (PR #218691)

[Gábor Tóthvári via cfe-commits]

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@@ -870,12 +859,11 @@ void ExprEngine::VisitUnaryOperator(const UnaryOperator* U, ExplodedNode *Pred,
     return Engine.makeNodeWithBinding(N, U, SV);
   };
 
-  for (ExplodedNode *N : CheckedSet) {
+  auto VisitUnaryOperatorImpl = [U, Pred, &Engine = Engine, this,
+                                 MakeNodeForIdentityOp](ExplodedNodeSet &Dst) {
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tigbr wrote:

I have reverted that UnaryOperator commit. See: [7cbe302](https://github.com/llvm/llvm-project/pull/218691/commits/7cbe3020a561dbd106c58dfebfe5ab230d341ee8). It was not NFC and I have not found an obvious NFC way to refactor it to the regular algorithmic scheme, so I figured that it is probably better to deal with it in a separate patch.

https://github.com/llvm/llvm-project/pull/218691