test: wallet_transactiontime_rescan.py failure with `--without-bdb`

[fanquake]

master @ cf06c9b

./autogen.sh
./configure --without-bdb
make -j9

./test/functional/wallet_transactiontime_rescan.py
2021-11-21T09:09:22.057000Z TestFramework (INFO): Initializing test directory /var/folders/z2/cn877pxd3czdfh47mfkmbwgm0000gn/T/bitcoin_func_test_vilmgmza
2021-11-21T09:09:22.950000Z TestFramework (INFO): Prepare nodes and wallet
2021-11-21T09:09:23.018000Z TestFramework (INFO): Start transactions
2021-11-21T09:09:24.212000Z TestFramework (INFO): Send 10 btc to user
2021-11-21T09:09:24.472000Z TestFramework (INFO): Send 5 btc to user
2021-11-21T09:09:25.834000Z TestFramework (INFO): Send 1 btc to user
2021-11-21T09:09:27.166000Z TestFramework (INFO): Check user's final balance and transaction count
2021-11-21T09:09:27.168000Z TestFramework (INFO): Check transaction times
2021-11-21T09:09:27.168000Z TestFramework (INFO): Restore user wallet on another node without rescan
2021-11-21T09:09:27.191000Z TestFramework (ERROR): Assertion failed
Traceback (most recent call last):
  File "/Users/michael/github/fanquake-bitcoin/test/functional/test_framework/test_framework.py", line 132, in main
    self.run_test()
  File "./test/functional/wallet_transactiontime_rescan.py", line 134, in run_test
    assert_equal(restorewo_wallet.getbalance(), 0)
  File "/Users/michael/github/fanquake-bitcoin/test/functional/test_framework/util.py", line 50, in assert_equal
    raise AssertionError("not(%s)" % " == ".join(str(arg) for arg in (thing1, thing2) + args))
AssertionError: not(1.00000000 == 0)
2021-11-21T09:09:27.246000Z TestFramework (INFO): Stopping nodes
2021-11-21T09:09:27.454000Z TestFramework (WARNING): Not cleaning up dir /var/folders/z2/cn877pxd3czdfh47mfkmbwgm0000gn/T/bitcoin_func_test_vilmgmza