Remove some code in libsvn_delta that assumes unaligned access is safe
and therefore breaks GCC's vectorizer. The new code also attempts to
make better use of the CPU data cache.

* subversion/libsvn_delta/text_delta.c
  (fast_memcpy): Simplify the short copy loop implementation.
  (patterning_copy): Do not blindly use unaligned word-size access.
   Keep the data cache hot when repeating a pattern.

Found by: Alan Modra
(Message-ID: <20140809135509.GC7047@bubble.grove.modra.org>)


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1618472 13f79535-47bb-0310-9956-ffa450edef68