All loadContents tests are required

Fixes #122

Author: mr-c

tests/loadContents/test-index.yaml

@@ -3,12 +3,12 @@
   id: cwloutput_nolimit
   output: {$import: compare-output.json}
   doc: "Test that loading from cwl.output.json isn't limited to 64k"
-  tags: [ command_line_tool ]
+  tags: [ command_line_tool, required ]
 
 - job: input.yml
   tool: loadContents-limit.cwl
   id: loadcontents_limit
   output: {}
   doc: "Test that loadContents on a file larger than 64k fails"
   should_fail: true
-  tags: [ command_line_tool ]
+  tags: [ command_line_tool, required ]