Check BooleanInCondition for while and for loop

[VincentLanglet]

See https://phpstan.org/r/2930c63b-1ea1-4711-9272-a4de8f998a82

In the while loop, 0 and null are treated the same way, which might create bugs (in the same way it can occur for if condition).

Same idea for the for loop condition $j which might be a typo, missing the real condition.

WDYT about extending the BooleanInCondition to while and for loop @ondrejmirtes ?

I dunno it the for loop need to allow empty expression like

for ($i = 1; ; $i++) {
    if ($i > 10) {
        break;
    }
    echo $i;
}

[ondrejmirtes]

Yeah, sure, makes sense. There are more blindspots:

• while
• do-while
• for

We might be able to find more by searching for $cond in PHP-Parser.