This test places 128 in positions that would not be found
in the VP9 filter tables.  The ssse3 code packs this table
into chars and uses the pmaddubsw instruction, which treats
the value as signed.  The ssse3 code checks for 128 in
position 3, skipping the ssse3 code if found, and calls
vp9_convolve8_c().  vp9_convolve8_c() is also used for scaling.
ChangeFilterWorks breaks the ssse3 scaling code found in other
commits.

Change-Id: I1f5a76834bc35180b9094c48f9421bdb19d3d1cb