[OpenJDK 2D-Dev] Initial implementation for batched AA-mask upload for xrender

[Clemens Eisserer]

Hi Sergey,

> Thank you for contribution! If there is a chance to implement it soon(at an
> early test stage) then it is possible to push this to jdk11 and enable it by
> default to expose all possible issues. If no issues will be found, then we
> can release it as-is, otherwise we can disable it by default via property.

Just to get some idea, how soon is soon? ;)
There shouldn't be a lot missing, however clean-ups wouldn't do any
harm to the code.

Thanks you in advance, Clemens