goalc: Get CodeTester tests passing on Arm64 (only targetting macOS atm) (#3290)

This PR does the following:
- Designs a mechanism by which arm64 instructions can be encoded and
emitted
- Dispatch our higher-level instruction emitting calls to either x86 or
arm64 instructions depending on what the compiler is set to (defaults to
x86)
- Bare minimum scaffolding to get the arm64 instructions successfully
executing atleast on apple silicon
- Implement enough instructions to get the codetester test suite passing
on arm

common/custom_data/TFrag3Data.cpp

@@ -3,14 +3,9 @@
 #include <algorithm>
 #include <functional>
 
-#ifndef __aarch64__
-#include "xmmintrin.h"
-#else
-#include "third-party/sse2neon/sse2neon.h"
-#endif
-
 #include "common/log/log.h"
 #include "common/util/Assert.h"
+#include "common/util/simd_util.h"
 
 namespace tfrag3 {