Create a module for interacting with the JIT from Lua code

[Leonardo2718]

There are many cases where it can be useful to interact with the JIT compiler from Lua code. Some useful interactions can be:

• checking whether a function has been compiled
• requesting a compilation
• turning the JIT off
• turning the JIT on
• blacklisting a function from compilation
• removing a function from the compilation blacklist

A Lua module seems like a clean way to encapsulate this interface. Implementing this will likely require redesigning the API between the VM and the JIT.