Only class IN is allowed for user-defined views; the internally
generated `_bind` view stays in the CH class. Both `named` and the
shared checker in `lib/isccfg/check.c` now reject non-IN views, so a
config can no longer pass `named-checkconf` yet fail to start in
`named`.
Tests, configs, and catalog zones using CH or arbitrary classes
(e.g. `class10`) are removed accordingly.
Send update messages for zones with CLASS0, ANY and NONE. The class
ANY UPDATE also attempts to delete a KX record in an existing IN
class zone to trigger a REQUIRE.
Test that the server is still running.
Send various UPDATE requests that are known to have caused
crashes previously with deliberately misconfigured non-IN
zones; confirm that UPDATE is not processed.
