tdb2: test: try (almost) all tests with TDB_VERSION1 flag.
There are some minor changes required, in particular:
1) Make sure lockcheck understands tdb1 allrecord lock upgrades.
2) Handle tdb1 sequence number jumps: various operations increment the
sequence number twice, especually tdb_append.
3) Don't test fail on unlock, since it gets triggered with traversal on the
tdb1 backend (we didn't actually ever test this case for tdb2).
4) Move clear_if_first to offset 4, to match tdb1.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
(Imported from CCAN commit
818ed29730b030ce79855fc35c212b51adff3180)