nodetool cluster repair without additional params repairs all tablet
keyspaces in a cluster. Currently, if a table is dropped while
the command is running, all tables are repaired but the command finishes
with a failure.
Modify nodetool cluster repair. If a table wasn't specified
(i.e. all tables are repaired), the command finishes successfully
even if a table was dropped.
If a table was specified and it does not exist (e.g. because it was
dropped before the repair was requested), then the behavior remains
unchanged.
Fixes: SCYLLADB-568.
Closesscylladb/scylladb#28739