* x64: expand FloatCC enum in ISLE
* isle: regenerate manifests
* isle: generate all enum fields in `clif.isle`
This expands the `gen_isle` function to write all of the immediate
`enum`s out explicitly in `clif.isle`. Non-`enum` immediates are still
`extern primitive`.
* Only compile `enum_values` with `rebuild-isle` feature
* Only compile `gen_enum_isle` with `rebuild-isle` feature