emit_x86: Introduce the concept of deferred emits

Remove the concept of the far code region

src/dynarmic/backend/x64/a32_emit_x64.cpp

@@ -155,6 +155,11 @@ A32EmitX64::BlockDescriptor A32EmitX64::Emit(IR::Block& block) {
     EmitX64::EmitTerminal(block.GetTerminal(), ctx.Location().SetSingleStepping(false), ctx.IsSingleStep());
     code.int3();
 
+    for (auto& deferred_emit : ctx.deferred_emits) {
+        deferred_emit();
+    }
+    code.int3();
+
     const size_t size = static_cast<size_t>(code.getCurr() - entrypoint);
 
     const A32::LocationDescriptor descriptor{block.Location()};

src/dynarmic/backend/x64/a64_emit_x64.cpp

@@ -126,6 +126,11 @@ A64EmitX64::BlockDescriptor A64EmitX64::Emit(IR::Block& block) {
     EmitX64::EmitTerminal(block.GetTerminal(), ctx.Location().SetSingleStepping(false), ctx.IsSingleStep());
     code.int3();
 
+    for (auto& deferred_emit : ctx.deferred_emits) {
+        deferred_emit();
+    }
+    code.int3();
+
     const size_t size = static_cast<size_t>(code.getCurr() - entrypoint);
 
     const A64::LocationDescriptor descriptor{block.Location()};

src/dynarmic/backend/x64/emit_x64.h

@@ -6,6 +6,8 @@
 #pragma once
 
 #include <array>
+#include <functional>
+#include <memory>
 #include <optional>
 #include <string>
 #include <type_traits>
@@ -14,6 +16,7 @@
 #include <mcl/bitsizeof.hpp>
 #include <tsl/robin_map.h>
 #include <tsl/robin_set.h>
+#include <xbyak/xbyak.h>
 #include <xbyak/xbyak_util.h>
 
 #include "dynarmic/backend/x64/exception_handler.h"
@@ -58,8 +61,16 @@ struct EmitContext {
 
     RegAlloc& reg_alloc;
     IR::Block& block;
+
+    std::vector<std::function<void()>> deferred_emits;
 };
 
+using SharedLabel = std::shared_ptr<Xbyak::Label>;
+
+inline SharedLabel GenSharedLabel() {
+    return std::make_shared<Xbyak::Label>();
+}
+
 class EmitX64 {
 public:
     struct BlockDescriptor {