Sync x64 emitter to Dolphin's.
MIPSTables: Annotate fp and hi/lo in/out more accurately than just "other"

Some typo fixes
Merge x64 emitter from a newer Dolphin version.

This one can generate slightly smaller code by exploiting some EAX-only
encoding and various other short forms, and adds support for many newer
CPU instructions.
Merge pull request #6989 from hrydgard/x86-emitter-merge

Merge from Dolphin's x86-64 emitter