minor: SingleSpaceAroundConstructFixer - support space before as

[paulbalandan]

Closes #5155

[SpacePossum]

Looking good.
Wondering, as 5155 is about foreach , does this fix also touch <?php use exception as bar; for example? Do we want to (I think so)? Maybe having some tests for this would be good.

[kubawerlos]

Maybe some tests with meaningful token before as like:

foreach (range(0, 9)as$i) { echo $i; }
foreach (range(0, 9)as $i) { echo $i; }

but I won't insist on adding them.

[Wirone]

Thank you @paulbalandan 🍻