Caused by missing check for end of partitions in prune range check


mysql-test/r/partition.result:
  Added test case for duplicate bug#21388
mysql-test/r/partition_range.result:
  Added new test case for bug#21339
mysql-test/t/partition.test:
  Added test case for duplicate bug#21388
mysql-test/t/partition_range.test:
  Added new test case for bug#21339
sql/sql_partition.cc:
  Check so that we don't set outer range to be larger than max_partition