Further reduce number of frames used in test

Change-Id: I5bc018b22690f47a6b4507da872bffde4b6983c8
diff --git a/test/aomcx_set_ref.sh b/test/aomcx_set_ref.sh
index a6ac73d..f51b73c 100755
--- a/test/aomcx_set_ref.sh
+++ b/test/aomcx_set_ref.sh
@@ -33,7 +33,7 @@
   local codec="$1"
   local output_file="${AOM_TEST_OUTPUT_DIR}/aom_cx_set_ref_${codec}.ivf"
   local ref_frame_num=4
-  local limit=20
+  local limit=10
   if [ ! -x "${encoder}" ]; then
     elog "${encoder} does not exist or is not executable."
     return 1