CID 281450: Dereference before null check (REVERSE_INULL)

test-async.c

162cleanup:
   	
CID 281450 (#1 of 1): Dereference before null check (REVERSE_INULL)
check_after_deref: Null-checking inst suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
163        if (result != ISC_R_SUCCESS && inst != NULL) {
164                plugin_destroy((void **)&inst);
165        }