We'd like to be able to support context-sensitive whitelists in
Painless but we can't now because the whitelist is a static thing.
This begins to de-static the whitelist, in particular removing
the static keyword from `Definition#getRuntimeClass` and plumbing
the static instance into the appropriate spots as though it weren't
static. Once we de-static all the methods we should be able to
fairly simply build context-sensitive whitelists.

The only "fun" bit of this is that I added another layer in the
chain of methods that bootstraps `def` calls. Instead of running
`invokedynamic` directly on `DefBootstrap` we now `invokedynamic`
`$bootstrapDef` on the script itself loads the `Definition` that
the script was compiled against and then calls `DefBootstrap`.

I chose to put `Definition` into `Locals` so I didn't have to
change the signature of all the `analyze` methods. I could have
do it another way, but that seems ok for now.