Description:
------------
When a function has a YIELD instruction inside a IF instruction, the yield instruction is called even if the IF INSTRUCTION is not true.

Tested whith 7.0.33, 7.1.26 and 7.2.14 versions.

Test script:
---------------
function gen_one_to_three($useYield = true)
{
    $result = [];
    for ($i = 1; $i <= 3; $i++) {
        if (true === $useYield) {
            yield $i;
        } else {
            $result[] = $i;
        }
    }

    if (false === $useYield) {
        return $result;
    }
}

$return1 = gen_one_to_three(true);
echo get_class($return1)
$return2 = gen_one_to_three(false);
echo get_class($return2);

Expected result:
----------------
Generator
PHP Warning:  get_class() expects parameter 1 to be object, array given

Actual result:
--------------
Generator
Generator