It fixes issues #14982 and #14724.
The main problem of upscaling a canvas is that it can induces some pixelation
(see issue #14724). So this patch is just removing the limit and as a side
effect it fixes issue #14982.
As far as I can tell, in looking different profiles (especially some memory profile)
in using the Firefox profiler, I don't see any noticeable difference in term of
memory use.
