`/regions/replicated` may return the wrong results

[rleungx]

Bug Report

Use /regions/replicated to query if the regions in the specified range are all replicated. But this API only checks the regions inside the waiting list which is not accurate and may return the wrong results. See

pd/server/api/region.go

Line 283 in fc55b44

for _, item := range rc.GetCoordinator().GetWaitingRegions() {

It is because the waiting list is shared by some checkers and saves 1000 regions at most. And in the recent modification, we only put the regions, which are filtered by the temporary store state, into it. Then, the result could be more misleading.