[JDBC Smart Driver] Connection count not found for a host when closing its connection

[ashetkar]

Jira Link: DB-3237

Description

From @ssherwood:
Also, I'm seeing this periodically in my logs after stopping the master leader:

2022-08-18 22:10:46.159 DEBUG 216146 --- [nnection closer] com.zaxxer.hikari.pool.PoolBase          : HikariPool-1 - Closing connection com.yugabyte.jdbc.PgConnection@1f2adb96 failed

java.lang.NullPointerException: Cannot invoke "java.lang.Integer.intValue()" because "currentCount" is null
	at com.yugabyte.ysql.ClusterAwareLoadBalancer.updateConnectionMap(ClusterAwareLoadBalancer.java:256) ~[jdbc-yugabytedb-42.3.5-yb-1.jar!/:42.3.5-yb-1]
	at com.yugabyte.jdbc.PgConnection.close(PgConnection.java:775) ~[jdbc-yugabytedb-42.3.5-yb-1.jar!/:42.3.5-yb-1]
	at com.zaxxer.hikari.pool.PoolBase.quietlyCloseConnection(PoolBase.java:137) ~[HikariCP-5.0.1.jar!/:na]
	at com.zaxxer.hikari.pool.HikariPool.lambda$closeConnection$1(HikariPool.java:444) ~[HikariCP-5.0.1.jar!/:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[na:na]
	at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]