Revert "Implement stack-locking for multi-engine support"

This is a short term backout until it gets fixed.

This reverts commit c30530f12663302869a8f2edf979e8a8bd33ed2d.
Closes-bug: #1250797

Change-Id: Ide1dc4a9d1469dee033e8bc08d8ab4da96f79fc0
Merge "Revert "Implement stack-locking for multi-engine support""