ImageData object must initialize to source when the source is provided

[Karl Dubost]

Test to reproduce the issue

var array = new Uint8ClampedArray(8);
var imgdata = new window.ImageData(array, 1, 2);
imgdata.data === array;


This returns false in Safari
and true in Firefox and Chrome.

The spec says:

> If source was given, then initialize the data attribute of imageData to source.
— https://html.spec.whatwg.org/multipage/canvas.html#initialize-an-imagedata-object


This makes Safari fail
https://github.com/web-platform-tests/wpt/blob/7a0b0c285b91a0b1fa08da58c964b82e5cf40733/html/canvas/element/pixel-manipulation/2d.imageData.object.ctor.array.html#L28
https://wpt.fyi/results/html/canvas/element/pixel-manipulation/2d.imageData.object.ctor.array.html?label=experimental&label=master&aligned

[Radar WebKit Bug Importer]

<rdar://problem/104284100>