[clang] [Analyzer][CFG] Correctly handle rebuilt default arg and default init expression (PR #117437)

[Hans Wennborg via cfe-commits]

zmodem wrote:

creduce'd reproducer:

```
$ cat /tmp/a.cc
class Location {
public:
  static Location Current(int = __builtin_LINE());
};
class DOMMatrix;
class BasicMember {
public:
  BasicMember(DOMMatrix *);
};
template <typename> using Member = BasicMember;
class ExceptionState {
public:
  ExceptionState &ReturnThis();
  ExceptionState(Location);
};
class NonThrowableExceptionState : public ExceptionState {
public:
  NonThrowableExceptionState(Location location = Location::Current())
      : ExceptionState(location) {}
};
class DOMMatrix {
public:
  static DOMMatrix *
  Create(int *, ExceptionState & = (NonThrowableExceptionState().ReturnThis()));
};
class CSSMatrixComponent {
  int CSSMatrixComponent_matrix;
  CSSMatrixComponent()
      : matrix_(DOMMatrix::Create(&CSSMatrixComponent_matrix)) {}
  Member<DOMMatrix> matrix_;
};
$ clang -c -Wunreachable-code-aggressive /tmp/a.cc
clang: /work/llvm-project/clang/lib/Analysis/CFG.cpp:822: void (anonymous namespace)::CFGBuilder::appendStmt(CFGBlock *, const Stmt *): Assertion `!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S' failed.
```

https://github.com/llvm/llvm-project/pull/117437