to make it posisble to diagnose from outside, if potential
BF victim transaction is blocked in replayer wait loop (before entering commit phase).
Also, added new forced state change to s_must_abort, if before_rollback() is used
for a transaction in s_committing state. Such situation can happen, if BF abort happens
for a victim, which has passed certification and moved to commit phase before the BF aborting happens.