If non-trivial alignment (e.g. 64) requested, and the object size
(e.g. 16) is smaller than (alignment_request -
MHEAP_ELT_OVERHEAD_BYTES), round up the size request.
This avoids creating remainder chunks, which are
false-cache-line-sharing bait to begin with.
Change-Id: Ie1a21286d29557d125bb346254b1be2def868b1a
Signed-off-by: Dave Barach <dave@barachs.net>