Added formatting test for multiple class guarded promises

We want to ensure empty newlines are added before each class guard
(except the first one in each bundle section).

Signed-off-by: Ole Herman Schumacher Elgesem <ole.elgesem@northern.tech>

Author: olehermanse

tests/format/007_class_guarded_empty_lines.expected.cf

@@ -0,0 +1,11 @@
+bundle agent main
+{
+  vars:
+    hpux::
+      "package_dir"
+        string => "$(sys.flavour)_$(sys.arch)";
+
+    !hpux::
+      "package_dir"
+        string => "$(sys.class)_$(sys.arch)";
+}

tests/format/007_class_guarded_empty_lines.input.cf

@@ -0,0 +1,10 @@
+bundle agent main
+{
+  vars:
+    hpux::
+      "package_dir"
+        string => "$(sys.flavour)_$(sys.arch)";
+    !hpux::
+      "package_dir"
+        string => "$(sys.class)_$(sys.arch)";
+}