Recommit of patch:
http://lists.mysql.com/commits/91400

Test case only (code part was pushes as bug-49028)

mysql-test/r/partition_column.result:
  Bug#48737: Partitions: search fails with ucs2
  
  added test case
mysql-test/t/partition_column.test:
  Bug#48737: Partitions: search fails with ucs2
  
  Added result