Suboptimal minification when safe logical assignments are possible

[Repro](https://esbuild.github.io/try/#dAAwLjI4LjEALS1taW5pZnkgLS10YXJnZXQ9ZXNuZXh0AGxldCBmb287CmZvbyA9IGZvbyB8fCAxOwpleHBvcnQge2Zvb30).

Basically using these flags:

```
--minify --target=esnext
```

And this input code:

```js
let foo;
foo = foo || 1;
export {foo}
```

We get this output code:

```js
let o;o=o||1;export{o as foo};
```

But I think we should really be getting this:

```js
let o;o||=1;export{o as foo};
```

I understand in the presence of setters and proxies this may lead to slightly different execution, but there are some basic cases where we are sure we are not triggering a setter nor a proxy trap, like this one, so presumably the better minification should be emitted.

Start with the linked esbuild reproduction using --minify --target=esnext and the JavaScript input shown. Trace the minifier's handling of logical assignments and determine the safety conditions described in the issue; done means the safe case emits ||= while preserving behavior where setters or proxy traps may differ.

Written by the indexing model from the issue text.