avcodec/dct-test: Print failure notice below the failed *dct

This makes it easier to see where a failure happens
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/dct-test.c

@@ -245,8 +245,10 @@ static int dct_error(const struct algo *dct, int test, int is_idct, int speed, c
            omse, ome, (double) sysErrMax / NB_ITS,
            maxout, blockSumErrMax);
 
-    if (spec_err && !dct->nonspec)
+    if (spec_err && !dct->nonspec) {
+        printf("Failed!\n");
         return 1;
+    }
 
     if (!speed)
         return 0;