journal: Relax boot ID and monotonic clock consistency checks

journal: Relax boot ID and monotonic clock consistency checks

The monotonic clock value consistency should only be checked if the boot
ID is the same as the last journal entry, and requiring that the current
boot ID be the same as the boot ID of the last entry is not necessary
for ensuring deterministic bisection as we already enforce strict
ordering of the real time clock value in a single journal file.

This fixes an issue where a new journal file is unnecessarily created
every boot, potentially wasting storage space.