re-use the same local drive used by remote-peer (#18645)

historically, we have always kept storage-rest-server
and a local storage API separate without much trouble,
since they both can independently operate due to no
special state() between them.

however, over some time, we have added state()
such as

- drive monitoring threads now there will be "2" of
  them per drive instead of just 1.

- concurrent tokens available per drive are now twice
  instead of just single shared, allowing unexpectedly
  high amount of I/O to go through.

- applying serialization by using walkMutexes can now
  be adequately honored for both remote callers and local
  callers.

cmd/erasure-sets.go

@@ -262,6 +262,10 @@ func (s *erasureSets) connectDisks() {
 			disk.SetDiskLoc(s.poolIndex, setIndex, diskIndex)
 			s.erasureDisks[setIndex][diskIndex] = disk
 			s.erasureDisksMu.Unlock()
+
+			globalLocalDrivesMu.Lock()
+			globalLocalSetDrives[s.poolIndex][setIndex][diskIndex] = disk
+			globalLocalDrivesMu.Unlock()
 		}(endpoint)
 	}