This patch adds a reproducer test for an issue #16382.
See scylladb/seastar#2044 for details of the problem.
The test is enabled only in dev mode since it requires
error injection mechanism. The patch adds a new injection
into storage_proxy::handle_read to simulate the problem
scenario - the node is shutting down and there are some
unfinished pending replica requests.
Closesscylladb/scylladb#16776