SQL where optimizer doesn't use ONEPASS strategy at all

Here's stub from box/sql/where.c:

int
sqlite3WhereOkOnePass(WhereInfo * pWInfo, int *aiCur)
{
        memcpy(aiCur, pWInfo->aiCurOnePass, sizeof(int) * 2);
        /*  Tarantool workaround: one pass is not working right now, since deleting tuple
         *  invalidates pointing iterator (which is used to go through table).
         */
        if (pWInfo->eOnePass == ONEPASS_MULTI) {
                pWInfo->eOnePass = ONEPASS_OFF;
        }
...

This means that ONEPASS_MULTI is not used at all. Comment states
that it was disabled due to instability of Tarantool's iterators during
tuple delete. But look like this is not the case and this optimization
might be enabled. Immediate enabling leads to test fails, so need to
investigate.

If this mode is not possible to enable: remove comment and refactor
the function (and everything around in call-graph) to remove this stub.

Start in box/sql/where.c at sqlite3WhereOkOnePass and reproduce the test failures after enabling ONEPASS_MULTI. Trace the surrounding call graph to determine whether Tarantool iterator invalidation is still a problem. Done means either enabling the optimization with passing tests or removing the workaround and refactoring the related stub and call graph.