64-bit VDSO
Similar to #690 but actually matters.
I've noticed with a lot of proton games that abuse `clock_gettime(CLOCK_MONOTONIC` very heavily, Calling it roughly every 51 MICROSECONDS! Considering the syscall itself can take 16-100 microseconds, this takes a wackload of time relatively.

Implementing VDSO so we can forward it to AArch64 VDSO to save cycles will give proton a significant performance boost.

I'll give this an implement since I've already spent time looking at the VDSO ELF format and what it takes to wire this up.