test: Add new ref image for jpeg test (AcademySoftwareFoundation#5007)

Needed for some systems after the changes of AcademySoftwareFoundation#4963.

Ever so slightly different LSB somewhere makes the hashes not match, but
it's a correct visual result.

Signed-off-by: Larry Gritz <lg@larrygritz.com>

Author: lgritz

testsuite/jpeg/ref/out-jpeg9.4.txt

@@ -0,0 +1,9 @@
+Reading src/YCbCrK.jpg
+src/YCbCrK.jpg       :   52 x   52, 3 channel, uint8 jpeg
+    SHA-1: B54FAE77E27EFCEACF27BA796A48DCE6DF262F26
+    channel list: R, G, B
+    jpeg:ColorSpace: "YCbCrK"
+    jpeg:subsampling: "4:4:4"
+    oiio:ColorSpace: "srgb_rec709_scene"
+Comparing "rgb-from-YCbCrK.tif" and "ref/rgb-from-YCbCrK.tif"
+PASS