ci: extract separate working_with_an_empty_struct_test.v

vlib/v/tests/fn_expecting_ref_but_returning_struct_test.v

@@ -1,4 +1,5 @@
 struct Foo {
+   x int
 }
 pub fn (f Foo) str() string { return 'Foo{}' }
 

vlib/v/tests/working_with_an_empty_struct_test.v

@@ -0,0 +1,12 @@
+struct EmptyStruct {}
+pub fn (f EmptyStruct) str() string { return 'EmptyStruct{}' }
+fn new_s() EmptyStruct {
+	println('>get_foo')
+	return EmptyStruct{}
+}
+
+fn test_using_an_empty_struct_compiles_and_works(){
+	s := new_s()
+	eprintln('s: $s')
+	assert true
+}