Make it possible to query the compiler to direct optimization

To optimize some methods as they are inlined it may be helpful to know 1) if the method is being inlined, and 2) which parameters (if any) are constant.

I have a patch to add these which is well contained, so I thought it would be worth committing.

The original target for this was arraycopy, but in order to get better array copy we also need to add new instructions and I currently do not have the time to do the required analysis/implementation.