This mini series contains two fixes that are bundled together since the
second one assumes that the first one exists (or it will not fix
anything really...), the two problems were:
1. When certain operations are called on a service level controller
which doesn't have it's data accessor set, it can lead to a crash
since some operations will still try to dereference the accessor
pointer.
2. The cql environment test initialized the accessor with a
sharded<system_distributed_data>& however this sharded class as
itself is not initialized (sharded::start wasn't called), so for the
same that were unsafe for null dereference the accessor will now crash
for trying to access uninitialized sharded instance.
Closes#9468
* github.com:scylladb/scylla:
CQL test environment: Fix bad initialization order
Service Level Controller: Fix possible dereference of a null pointer
4bfaa7d9fc