reference format obtained doesn't need further validation (#8964)

we don't need to validateFormats again once we have obtained
reference format, because it is possible that at this stage
another server is doing a disk heal during startup, once
in a while due to delays we get false positives and our
server doesn't start.

Format in quorum as reference format can be assumed as valid
and we proceed further, until and unless HealFormat re-inits
the disks after a successful heal.

Also use separate port for healing tests to avoid any
conflicts with regular build testing.

Fixes #8884

cmd/background-heal-ops.go

@@ -75,6 +75,7 @@ func (h *healRoutine) run() {
 				break
 			}
 
+			// Wait and proceed if there are active requests
 			waitForLowHTTPReq(int32(globalEndpoints.Nodes()))
 
 			var res madmin.HealResultItem