media/test: Update video thumbnail MD5 sums

CL:989024 updated the MD5 sums for the video_VideoDecodeAccelerator
test, but thanks to the magic of copy and paste, the VP8 sum ended up
being the same as the VP9 sum. Fix that.

BUG=827032
TEST=video_VideoDecodeAccelerator
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Pawel Osciak <posciak@chromium.org>

TBR=dalecurtis@chromium.org,posciak@chromium.org

Change-Id: If55a5371c45ae01103f80f4007df8e7338570142
Reviewed-on: https://chromium-review.googlesource.com/994068
Commit-Queue: Ricky Liang <jcliang@chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548410}

media/test/data/test-25fps.vp8.md5

@@ -9,4 +9,4 @@ cd355b553ce7660283c52675232e9227
 # Intel - go2001
 f9c98d3808b3ca06d3375d005ab31537
 # Intel - VA decode to NV12, EGLImage CSC
-919bee0d8a8278eeebb2c198a6b51455
+4fc4e3c4b690c004072b968530058b67