Major Description
Daffodil has three validation modes: off, limited, and full. "Limited" enables Daffodils internal validation during parsing and "full" enables Xerces validation at the end of parsing. However, "full" also enables Daffodils limited validation, so we incur extra overhead with full validation.
We should change full validation so it only does Xerces validation. Note that this change is not backwards compatible and could potentially break tests that use full validation but specifically look for Daffodil validation messages.
Alternatively, we may want to consider adding a new validation mode that only enables xerces. Then "full" could keep its current behavior of validating with Daffodil and Xerces. This has the added benefit that we can get complete test coverage of both validation mechanisms without having to duplicate tests.