Remove Preprocessor_HipHop

To reduce the maintenance burden for changes such as Id7ec4e69. The
project to optimise the preprocessor for hiphop is incomplete and is not
especially useful given the present state of hiphop support.

Change-Id: Iebcfe4d40f74520e29e7feb522251892fab2f652
Merge "Remove Preprocessor_HipHop"