regtest: split reference files allowing tests to run individually

[ffmpeg] / tests / ref / vsynth2 / asv1

4eb34d2de25f67a2706456e999338fe9 *./tests/data/a-asv1.avi
832512 ./tests/data/a-asv1.avi
c96ff7fd17c52f99ddb7922a4cb9168f *./tests/data/asv1.vsynth2.out.yuv
stddev:   10.47 PSNR: 27.73 bytes:  7603200/  7603200