HIVE-5668: path normalization in MapOperator is expensive (Thejas Nair reviewed by Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1536845 13f79535-47bb-0310-9956-ffa450edef68
Merge latest trunk into branch. (Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/tez@1536918 13f79535-47bb-0310-9956-ffa450edef68