[Issue 24395] Allow braced statements in loop conditions

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24395

--- Comment #1 from Bolpat <qs.il.paperinik at gmail.com> ---
Can also be extended to `if` statements:
```d
if ({ auto x = f(); !x.empty; }) { }
```

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