Changes for Hadoop Native Map Output Collector
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MAPREDUCE-5985. native-task: Fix build on macosx. Contributed by Binglin Chang
MAPREDUCE-5994. Simplify ByteUtils and fix failing test. (todd)
MAPREDUCE-5996. native-task: Rename system tests into standard directory layout (todd)
MAPREDUCE-5997. native-task: Use DirectBufferPool from Hadoop Common (todd)
MAPREDUCE-6000. native-task: Simplify ByteBufferDataReader/Writer (todd)
MAPREDUCE-5991. native-task should not run unit tests if native profile is not enabled. (Binglin Chang)
MAPREDUCE-5995. native-task: Revert changes to Text internals (todd)
MAPREDUCE-6005. native-task: Fix some valgrind errors (Binglin Chang)