This reverts commit 135b91aecd9be1f6f5806b667e07e383dd481198.

"endsWithBreak()" is not a meaningful question to ask and should not be
used this way. A simple example that defeats this logic is:

```zig
export fn entry() void {
    outer: {
        {
            break :outer;
        }
        return;
    }
}
```