Doing this to be able to create a test with a syntax error on a separate
file.

This commit adds the following groups of tests:

- A few tests that do not trigger the sniff but should help to
protect against regressions in the future. Including tests using the for
loop alternative syntax.
- A test to exercise code in the sniff to bail early if the `for` keyword is
found without a opening parenthesis. This part was not covered before.

This commit fixes an issue in the sniff that could result in the following E_DEPRECATED
error when running PHP 8.3:

```
Decrement on type null has no effect, this will change in the next major version of PHP

src/Standards/Generic/Sniffs/CodeAnalysis/ForLoopShouldBeWhileLoopSniff.php:65
```

This sniff relies on finding the position of the open and closing
parentheses for a given `for` loop. However, the problem was that there was
no defensive code for cases when the closing parenthesis is missing. The
sniff would still work when running PHP >= 8.2, but on PHP 8.3 it would
throw the deprecated message above.

This would happen because since there is no closing parenthesis `$end` is set to null,
and $next <= $end always evaluates to false
(https://github.com/PHPCSStandards/PHP_CodeSniffer/blob/84acf4e56f110db8e75cb9a575c5727df637643c/src/Standards/Generic/Sniffs/CodeAnalysis/ForLoopShouldBeWhileLoopSniff.php#L74).

The issue was fixed by bailing early if the closing parenthesis is
missing. A test with a `for` loop without the closing parenthesis was added.