Remove recursion from heap containers getOffsets helper function
Remove recursion from heap containers getOffsets helper function

Summary:
Avoid stack overflow and speed up getOffsets function, needed for performing heap container insertion.

(Note: this ignores all push blocking failures!)

Reviewed By: Gownta

Differential Revision: D35652300

fbshipit-source-id: 8cd98f294dcfb6be8baed726083e99e2652d63ad

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly