Skip large files when fuzzing with valgrind

They run the buildbot out of memory, so just skip them, we don't want to remove
them from the menagerie entirely.

("large" here is > 20000 KB, but that could change)

Change-Id: I58dd9a981be6e6fc661ea624cc0c5258a5986a9f
Ping-Bug: 11395
Reviewed-on: https://code.wireshark.org/review/9768
Reviewed-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

tools/fuzz-test.sh

@@ -157,6 +157,11 @@ while [ \( $PASS -lt $MAX_PASSES -o $MAX_PASSES -lt 1 \) -a $DONE -ne 1 ] ; do
         fi
         echo -n "    $CF: "
 
+        if [ $VALGRIND -eq 1 -a `ls -s $CF | cut -d' ' -f1` -gt 20000 ]; then
+            echo "Too big for valgrind"
+            continue
+        fi
+
         "$CAPINFOS" "$CF" > /dev/null 2> $TMP_DIR/$ERR_FILE
         RETVAL=$?
         if [ $RETVAL -eq 1 ] ; then