Placement rule in SQL isn't compatible with rule checker when using location labels

[rleungx]

Bug Report

What did you do?

Consider we have a cluster (three zones, each zone has a host, and each host has multiple instances)

zone1 --- host1 --- ap --- (kv1, kv2)
zone2 --- host2 --- ap --- (kv3, kv4)
zone3 --- host3 --- tp --- (kv5, kv6)

If we create the following placement policy:

create placement policy p leader_constraints="[+type=ap]" follower_constraint={+type=ap:1, +type=tp:1}", survival_preferences="[host]";

What did you expect to see?

The region peer won't be distributed in the same host.

What did you see instead?

There will be three rules in PD, and each of them has a location label setting. However, each rule's count is 1, and the location label only takes effect in one rule.

So, we still can find two replicas of a region in a host.

What version of PD are you using (pd-server -V)?

master

[bufferflies]

it needs to cherry pick release-6.5 again