Add --show-program-output option to shell tests.

When used --show-program-output shows the output from the programs run
during testing.

Change-Id: I15a47c43d1fcf0243c8df1a75d0d2a584ae1f08f
diff --git a/test/simple_encoder.sh b/test/simple_encoder.sh
index 13f5e29..6232093 100755
--- a/test/simple_encoder.sh
+++ b/test/simple_encoder.sh
@@ -31,8 +31,9 @@
 
   [ -x "${encoder}" ] || return 1
 
-  "${encoder}" "${codec}" "${YUV_RAW_INPUT_WIDTH}" "${YUV_RAW_INPUT_HEIGHT}" \
-      "${YUV_RAW_INPUT}" "${output_file}" 9999 > /dev/null 2>&1
+  eval "${encoder}" "${codec}" "${YUV_RAW_INPUT_WIDTH}" \
+      "${YUV_RAW_INPUT_HEIGHT}" "${YUV_RAW_INPUT}" "${output_file}" 9999 \
+      ${devnull}
 
   [ -e "${output_file}" ] || return 1
 }