[Experiment] Static Sends

[guillep]

Add static send bytecode, activating a given method instead of doing a lookup. The method to activate is stored in the literal frame.

This PR for now includes:

• the new bytecode
• extensions to the Opal compiler to generate the bytecode
• simple support for recursive static calls
• examples defining a factorial method

This PR misses:

• syntax support
• JIT support
• invalidation if the called method changes
• indirect recursion support

Some small benches:

[17 lateBoundRecursiveFactorial.] bench. "'2774597.961 per second'"
[17 staticBoundRecursiveFactorial.] bench.  "'3693598.280 per second'"
[17 staticBoundRecursiveFactorialHardcore.] bench. "'2170939.636 per second'"

[Ducasse]

why on this repo and the evref one?