MXS-1300: Add more MaxCtrl cluster tests

Added scripts that start two MaxScale on the same machine. This allows the
cluster synchronization commands to be tested locally.

test/stop_double_maxscale.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+#
+# This script is run after each test block. It kills the two MaxScale processes
+# and cleans up the directories that contain generated files.
+#
+
+maxscaledir=$MAXSCALE_DIR
+
+test -z "$MAXSCALE_DIR" && exit 1
+
+for ((i=0;i<20;i++))
+do
+    pkill '^maxscale$' || break
+    sleep 0.5
+done
+
+# If it wasn't dead before, now it is
+pkill -9 '^maxscale$'
+
+rm -r $maxscaledir/lib/maxscale
+rm -r $maxscaledir/cache/maxscale
+rm -r $maxscaledir/run/maxscale
+test -f /tmp/maxadmin.sock && rm /tmp/maxadmin.sock
+test -f /tmp/maxadmin2.sock && rm /tmp/maxadmin2.sock
+
+mkdir -m 0755 -p $maxscaledir/lib/maxscale
+mkdir -m 0755 -p $maxscaledir/cache/maxscale
+mkdir -m 0755 -p $maxscaledir/run/maxscale