add flag for transactional CS changes

b/267234374 was merged to V without a flag to gate the new logic.
This CL gates all the changes in b/267234374 and updates 2 tests.

Fixes: 309541257
Bug: 267234374 (root bug)
Test: 2 modified tests
Change-Id: I26967870b19be3670248ea237ccd8198f624c079
5 files changed