Code generator updates and fix for a union with a discriminator referencing an enum type.

[ckenna]

The QAPI has changed again. More fields have been added since April 23.

This also exposed a bug in the way that CpuInfoFast was being generated. The bug has to do with the way Java names are generated when there is a union with a discriminator referencing an enum type. So there's a commit in here to handle that case.

Also, this added more parameters to some options, so I had to go and fix some tests to add the new parameters.