[scudo] Adjust page map buffer size

Given the memory group, we are unlikely to need a huge page map to
record entire region. This CL reduces the size of default page map
buffer from 2048 to 512 and increase the number of static buffers to 2.

Reviewed By: cferris

Differential Revision: https://reviews.llvm.org/D144754

GitOrigin-RevId: c514198e4d39743369377011a55e74a8640b08f4
Change-Id: I301c818dee5775546c19640865167344145c5795
3 files changed