[ARM64] Initial commit for arm64 backend

Based entirely off existing xbyak x86 implementation and available
tests. Still needs a lot of optimization and testing on non-Windows
platforms.

So far passes all tests and boots at least some games on Windows.

CMakePresets.json

@@ -23,6 +23,22 @@
       },
       "architecture": "x64",
       "binaryDir": "${sourceDir}/build"
+    },
+    {
+      "name": "vs-arm64",
+      "displayName": "Visual Studio 2022 (ARM64)",
+      "generator": "Visual Studio 17 2022",
+      "condition": {
+        "type": "equals",
+        "lhs": "${hostSystemName}",
+        "rhs": "Windows"
+      },
+      "architecture": "ARM64",
+      "toolset": "host=x64",
+      "binaryDir": "${sourceDir}/build/vs-arm64",
+      "cacheVariables": {
+        "CMAKE_SYSTEM_PROCESSOR": "ARM64"
+      }
     }
   ],
   "buildPresets": [
@@ -58,6 +74,21 @@
       "name": "vs-checked",
       "configurePreset": "vs",
       "configuration": "Checked"
+    },
+    {
+      "name": "vs-arm64-debug",
+      "configurePreset": "vs-arm64",
+      "configuration": "Debug"
+    },
+    {
+      "name": "vs-arm64-release",
+      "configurePreset": "vs-arm64",
+      "configuration": "Release"
+    },
+    {
+      "name": "vs-arm64-checked",
+      "configurePreset": "vs-arm64",
+      "configuration": "Checked"
     }
   ]
 }