Provide a central and complete implementation for handling FSFS quirks in committed node revisions.
Provide a central and complete implementation for handling FSFS quirks
in committed node revisions.

At the moment, there are two: a workaround issue #4031 and the fact that
the fulltext size may be missing for PLAIN representations.

This patch does not remove all the local workarounds for these problems.
We should also add specific tests for these quirks.

DO NOT BACKPORT.

* subversion/libsvn_fs_fs/cached_data.c
  (fixup_expanded_size,
   fixup_node_revision): New helper functions.
  (get_node_revision_body,
   block_read_noderev): Let the new helpers do the fixup.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1673875 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion