Fix comparison when layout differs

[serpent7776]

In case layoutDifference is true compColor is assigned incorrect pixel value read from base instead of comp.

[dmtrKovalenko]

It would be amazing if you can add a test case that would fail with the previous implementation

[serpent7776]

I have no idea how to add new image files, because they are not being copied to the _build dir by dune.

[dmtrKovalenko]

intersting we have one of the existing tests failing could you please elaborate more on why do you think the existing test is wrong

[serpent7776]

I can understand that current value of 399 comes from difference in the image sizes, but now there's 18 more pixels. I don't know how antialiased comparison works, so I don't know why.

[serpent7776]

The following pixels are considered different (where previously weren't) after this fix:

x,y
90,0
93,0
94,0
95,0
96,0
103,0
104,0
105,0
106,0
109,0
0,90
0,93
0,95
0,96
0,103
0,104
0,106
0,109

[serpent7776]

I added a new test. Locally I had to copy the new images manually to _build directory for whatever reason.

[serpent7776]

I updated expects for the failing test 🤷