RFR: More promotion fixes

Fri May 14 12:00:17 UTC 2021

On Thu, 13 May 2021 23:57:06 GMT, William Kemper <wkemper at openjdk.org> wrote:

> This PR addresses a few issues with region promotion:
> * Fix typo in code which loops over continuation regions of humongous objects
> * Don't rely on mark bits above TAMS when iterating oops
> * Due to an as-yet-undiagnosed bug, we need to mark the cards for an entire region dirty when it's promoted

Looks good!

-------------

Marked as reviewed by rkennke (Lead).

PR: https://git.openjdk.java.net/shenandoah/pull/39