Warnings included in serialized DataProcessor

When a schema is compiled and serialized, any warnings that were created as part of the compilation are also serialized. Which means a reloaded DataProcessor includes those same warnings that were output during compilation.

DAFFODIL-2267 modified the CLI so that it does not output any diagnostics on a reloaded DataProcessor, but API users could still output those diagnostics which is likely not what they want. Reloaded parsers really show have no diagnostics associated with them.

Note that these reloaded warning diagnostic do not become part of the Parse/UnparseResult diagnostics. So even if API users output warnings on a reloaded DataProcessor, they at least won't see them for every parse.

But to avoid the possibility of these excess warnings, we should modify the save parser function so that it removes all diagnostics from the DataProcessor when saved.