runtime: have mergeInlineMarkBits also clear the inline mark bits
This is conceptually simpler, as the sweeper doesn't have to worry about
clearing them separately. It also doesn't have a use for them.
This will also be useful to avoiding unnecessary zeroing in
initInlineMarkBits at allocation time. Currently, because it's used in
both span allocation and at sweep time, we cannot blindly trust
needzero.
This change also renames mergeInlineMarkBits to moveInlineMarkBits to
make this change in semantics clearer from the name.
For #73581.
Change-Id: Ib154738a945633b7ff5b2ae27235baa310400139
Reviewed-on: https://go-review.googlesource.com/c/go/+/687936
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com>