fate: work around non-standard wc implementations

On some systems, the wc command prints spaces before the first
number causing mismatches with the test references.  Using the
output of wc as arguments to echo removes any extra whitespace.
Signed-off-by: Mans Rullgard <mans@mansr.com>

tests/regression-funcs.sh

@@ -67,7 +67,7 @@ do_avconv()
     elif [ $f = $pcm_dst ] ; then
         $tiny_psnr $f $pcm_ref 2
     else
-        wc -c $f
+        echo $(wc -c $f)
     fi
 }
 
@@ -82,7 +82,7 @@ do_avconv_nomd5()
     elif [ $f = $pcm_dst ] ; then
         $tiny_psnr $f $pcm_ref 2
     else
-        wc -c $f
+        echo $(wc -c $f)
     fi
 }