Coverity analysis defect 135130: Resource leak

Resource leak

The system resource will not be reclaimed and reused, reducing the future availability of the resource. Leak of memory or pointers to system resources
/test/csuite/wt10461_skip_list_stress/main.c:141: RESOURCE_LEAK 135130 Assigning: "check_key.data" = storage returned from "dmalloc(3UL)".
/test/csuite/wt10461_skip_list_stress/main.c:142: RESOURCE_LEAK 135130 Resource "(char *)check_key.data" is not freed or pointed-to in "sprintf".
/test/csuite/wt10461_skip_list_stress/main.c:153: RESOURCE_LEAK 135130 Variable "check_key" going out of scope leaks the storage "check_key.data" points to.