Revert "OnDiskHashTable: Use EndianStream.h to write little endian ostreams"

This reverts commit r205044.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205047 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "OnDiskHashTable: Use Endian.h to read little endian ostreams"

This reverts commit r205045.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205048 91177308-0d34-0410-b5e6-96231b3b80d8