DERBY-6125 Code clean up in client driver.

    Patch "derby-6125-visibility-03-a" to limit sharing of state
    between classes not in the same package by cloning arrays not
    considered performance sensitive.

    * ClientStatement
      made indexOfCurrentResultSet private by adding accessors

      removed unused field numInvisibleRS

      cloned execute, executeLargeUpdate and executeUpdate's overloads
      input arrays columnIndexes and columnNames

      cloned completeExecuteCall's argument resultSets

    * ClientPreparedStatement

      use new accessor resetResultSetList instead of accessing
      ClientStatement#indexOfCurrentResultSet directly

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1478641 13f79535-47bb-0310-9956-ffa450edef68