Add integration tests for shortnames expanding to correct resources

This adds new integration tests to test shortnames and
singular names are expanding to correct resources.

In this case, core types have always higher precendence than
CRDs.

test/cmd/legacy-script.sh

@@ -505,6 +505,12 @@ runTests() {
 
   record_command run_assert_short_name_tests
 
+  #########################
+  # Assert singular name  #
+  #########################
+
+  record_command run_assert_singular_name_tests
+
   #########################
   # Assert categories     #
   #########################