Description of problem:

If the JVM configuration should be edited for a host, assuming there is current no one, it is not possible to add a configuration without specifying the heap sizes.
This is possible if the CLI interface is used. The configuration is inherited from the JVM at host level with the same name.

The console should check whether there is a valid setting and allow to override it without mandatory settings if declared at host JVM


How reproducible:
Use the provided default domain configuration and navigate to 
Domain -> Host (master) -> Server configuration
edit the JVM settings on the JVM tab
set name "default" and apply JVM options
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Save will fail because the heap settings is mandatory

Expected results:
Should be possible to save partial settings if the domain/host contains correct defaults.