[scudo] Fix RingBuffer initialization.

Several map implementations require that map calls provide a page
aligned size.

Reviewed By: fmayer

Differential Revision: https://reviews.llvm.org/D141630

GitOrigin-RevId: 3fb470fe67cda25fd2ca74162727fd3c38eb0b11
Change-Id: I0280a22fcf3e2b06f842cf8c03efceeb409fc3ac
1 file changed