diff.c: do not use a separate "size cache".
diff.c: do not use a separate "size cache".

diff_filespec has a slot to record the size of the data already,
so make use of it instead of a separate size cache.

Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git