Redundant cast to Int preserve type

[orklah]

This PR conserve the type of an int expression that passes through an int cast. Before this PR, it was widened to TInt: https://psalm.dev/r/7f34cf6a8d

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/7f34cf6a8d

<?php

/**
 * @param positive-int $i
 * @return positive-int
 */
function takesAnInt(int $i) {
    return (int)$i;
}

Psalm output (using commit 1195335):

ERROR: RedundantCast - 8:12 - Redundant cast to int

INFO: LessSpecificReturnStatement - 8:12 - The type 'int' is more general than the declared return type 'positive-int' for takesAnInt

INFO: MoreSpecificReturnType - 5:12 - The declared return type 'positive-int' for takesAnInt is more specific than the inferred return type 'int'

[muglug]

Thanks!