wal: fix transaction boundaries for replicated transactions

Transaction boundaries were not updated correctly for transactions in
which local space writes were made from a replication trigger. Existing
transaction boundaries and row flags from the master were written as is
on the replica. Actually, the replica should recalculate transaction
boundaries and even WAIT_SYNC/WAIT_ACK flags.

Transaction boundaries should be recalculated when a replica appends a
local write at the end of the master's transaction, and
WAIT_SYNC/WAIT_ACK should be overwritten when nopifying synchronous
transactions coming from an old term.

The latter fix has uncovered the bug in skipping outdated synchronous
transactions: if one replica replaces a transaction from an old term
with NOPs and then passes that transaction to the other replica, the
other replica raises a split brain error. It believes the NOPs are an
async transaction form an old term. This worked before the fix, because
the rows were written with the original WAIT_ACK = true bit. Now this
is fixed properly: we allow fully NOP async tranasctions from the old
term.

Closes #8746

NO_DOC=bugfix
NO_CHANGELOG=covered by the next commit

(cherry picked from commit 099cb2da)