This change makes (*mheap).sysAlloc take an explicit list of hints and a
boolean as to whether or not any newly-created heapArenas should be
registered in the full arena list.
This is a refactoring in preparation for arenas.
For #51317.
Change-Id: I0584a033fce3fcb60c5d0bc033d5fb8bd23b2378
Reviewed-on: https://go-review.googlesource.com/c/go/+/432078
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>