fate: Add missing reference file from 9b4767e4.

tests/ref/fate/vp3-coeff-level64

+0, 0, 4617600, 0x4ba6df50
+0, 6000, 4617600, 0x419fdeaf
+0, 12000, 4617600, 0xeb2edced
+0, 18000, 4617600, 0xa2bb3a1a
+0, 24000, 4617600, 0x411cfb36
+0, 30000, 4617600, 0xb2dc22ed
+0, 36000, 4617600, 0x236d23b5
+0, 42000, 4617600, 0x7fef275e