This was introduced by the recent change in #11692 which prevented a
down-sizing rehashing while there is a fork.
## Solution
1. Fix the rehashing code, so that the same as it allows rehashing for up-sizing
during fork when the ratio is extreme, it will allow it for down-sizing as well.
Co-authored-by: Oran Agra <oran@redislabs.com>
This is a partial cherry pick of:
(cherry picked from commit b00a235186)
(cherry picked from commit d4c37320382edb342292a3e30250d46896a12016)
a1589c3769