evas: disable use of mmap on windows for allocating pixels buffer.

evas: disable use of mmap on windows for allocating pixels buffer.

We do have mmap provided by Evil, but there is no implementation yet of
an anonymous map support. Also it is not clear how the memory system of
windows does actually work, so not sure this optimization is relevant
to windows at all. Thus we disable it for the time being and unbreak
the windows support.

- cherry-pick me -