* Add codegen test for namespaced unions
* [Rust] Handle cross-namespace union use
* [Rust] Test namespace handling
* [Rust] Drop trailing whitespace in codegen
* [Rust] Set flags in generate_code.bat to match .sh
* [C#] Add additional namespace test file
Dart schema compiler generated a static getter for enum values, which
always created a new map instance for its callers. See #5819.
Now it generates const map for better performance
and readability.
