Summary:
Earlier approach used to allocate queryId randomly. This can make queryId to be 0, or equal to another queryId. Current diff fixes this.
Jira: DB-14703

Test Plan: yb_build.sh --java-test 'org.yb.pgsql.TestYbQueryDiagnostics#testYbCancelDiagnostics'

Reviewers: asaha

Reviewed By: asaha

Differential Revision: https://phorge.dev.yugabyte.com/D40964