OffscreenCanvas size.attributes.parse.empty test is not valid

[Cwiiis]

This test tests that setting width or height to an empty string has no effect, but I don't believe this is a valid reading of the spec. The width and height properties are unsigned longs - An empty string is equivalent to +0 according to the spec https://tc39.es/ecma262/#sec-tonumber and the OffscreenCanvas spec makes no mention (that I see) of 0 being an invalid value for width or height. As far as I can tell, a correct implementation of OffscreenCanvas would fail this test.

[zcorpan]

The test is offscreen-canvas/the-offscreen-canvas/size.attributes.parse.empty.html?

cc @xidachen

[Cwiiis]

The test is offscreen-canvas/the-offscreen-canvas/size.attributes.parse.empty.html?

That's correct.