Currently, when the tablet repair is started, info regarding
the operation is kept in the system.tablets. The new tablet states
are reflected in memory after load_topology_state is called.
Before that, the data in the table and the memory aren't consistent.
To check the supported operations, tablet_virtual_task uses in-memory
tablet_metadata. Hence, it may not see the operation, even though
its info is already kept in system.tablets table.
Run read barrier in tablet_virtual_task::contains to ensure it will
see the latest data. Add a test to check it.
Fixes: #21975.
Closesscylladb/scylladb#21995
610a761ca2