[clang] [Clang] Initialize bypassed variables w/ trivial-auto-var-init (PR #181937)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic commented:

This is a little different from gcc.  Consider, for example:

```
void g(int*);
void f() {
    while (true) {
        goto X;
        int x;
        X:
        g(&x);
    }
}
```

This patch initializers "x" once, before the loop.  gcc initializes "x" each loop iteration.

I'm not sure how much that difference matters in practice.

https://github.com/llvm/llvm-project/pull/181937