`FunctionHook` should support using an absolute jump patch if the user requests it

We would not want this to be the default, but if the user knows that the target function can accommodate an absolute jump (which could take up to 14 bytes), then we should support using one.

When using an absolute jump patch, we can allocate the trampoline anywhere in the address space, alleviating the fragmentation issue that normally plagues 64-bit function hooking.