[lacatoire]

imageaffine() names the wrong argument when an element of $affine has an unsupported type: the error blames $clip, but the matrix is the $affine argument.

To reproduce

<?php
try {
    imageaffine(imagecreatetruecolor(20, 20), [1, 0, null, 1, 0, 0]);
} catch (Throwable $e) {
    echo $e::class, ': ', $e->getMessage(), "\n";
}

Before (8.4.26 and 8.5.12):

TypeError: imageaffine(): Argument #3 ($clip) contains invalid type for element 2

After:

TypeError: imageaffine(): Argument #2 ($affine) contains invalid type for element 2