Fixed is_empty assertion in #1203 , but simulator still has error.
```sh
[ERROR] error Internal error: select '(engrossing_berger < X'6566651A3C70278D4E200657551D8071A1' AND competitive_petit > 1236742147.9451914)' should return no values for table 'super_becky'
```
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#1308
"Open a new cursor P1 to a transient table. The cursor is always opened read/write even if the main database is read-only. The ephemeral table is deleted automatically when the cursor is closed.
If the cursor P1 is already opened on an ephemeral table, the table is cleared (all content is erased)."
There is still some work to do, but this is a basic setup
Passing 1s and 0s with comments is not rustacean, and since we already follow the pattern of struct flags in other sections of the codebase it's better use it here too.
iteration direction must be known when seeking, and transitively
when using move_to() since seek() uses it, but otherwise IterationState
just brings way too much noise to the code -- it was meant to encode
invariants about how a cursor can be iterated, but it's not worth it.
iteration direction for seek()/move_to() can be inferred from the
SeekOp:
GE/GT/EQ: forward
LT/LE: backward
and get_next_record()/get_prev_record() already have different
logic for their respective iteration directions.
Prevoiusly we would overwrite even though size less than cell size. This
was wrong because it didn't update any fragment size or free blocks it
could. To be safe let's just overwrite only if local size is the same
amount.
Cell index doesn't move in `move_to` unless we don't need to check next
cell. On the other hand, with rightmost pointer, we advance cell index
by 1 even though where we are moving to was to that page
