Query system code in the exec/ directory which predates the introduction of RecordId still has variable names which refer to DiskLoc. This is an MMAP-specific type, so we should update the variable names to refer to RecordId.

For example, the enum values in WorkingSetMember::MemberState could be updated as follows:

• LOC_AND_IDX => RID_AND_IDX
• LOC_AND_UNOWNED_OBJ => RID_AND_UNOWNED_OBJ
• LOC_AND_OWNED_OBJ => RID_AND_OWNED_OBJ

Several PlanStages use 'loc' as variable name and need to be updated. For example:

https://github.com/mongodb/mongo/blob/fb64ed6b43a0b554b462af6a1171edb7b86ef7c8/src/mongo/db/exec/sort.h#L263