randomAccess parallel tuplesorts are disallowed because the leader would
try to write to its own leader tape, not because the leader would try to
write to a worker tape directly.
Cleanup from commit
9da0cc35284.
* Compute number of hole blocks so that we can later work backwards, and
* instrument number of physical blocks. We don't simply use physical
* blocks directly for instrumentation because this would break if we ever
- * subsequently wrote to worker tape.
+ * subsequently wrote to the leader tape.
*
* Working backwards like this keeps our options open. If shared BufFiles
* ever support being written to post-export, logtape.c can automatically