Make the test added in r1654933 somewhat more robust by using the parser / serializer functions provided by FSFS.
Make the test added in r1654933 somewhat more robust by using the
parser / serializer functions provided by FSFS.

* subversion/tests/libsvn_fs_fs/fs-fs-pack-test.c
  (stringbuf_find): Just return a position, not a pointer.
  (plain_0_length): Modify the revision content using FSFS noderev I/O and
                    tweak the native structure instead of its serialized
                    format.

Suggested by: danielsh

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1655008 13f79535-47bb-0310-9956-ffa450edef68

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