Patch extrq (#943)

* Use a singleton for instruction decoding

* Use singleton class

* Patch `EXTRQ`

* Fixup signal context functions

* Update CMakeLists.txt

---------

Co-authored-by: georgemoralis <giorgosmrls@gmail.com>

src/common/decoder.h

@@ -0,0 +1,29 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <Zydis/Zydis.h>
+#include "common/singleton.h"
+#include "common/types.h"
+
+namespace Common {
+
+class DecoderImpl {
+public:
+    DecoderImpl();
+    ~DecoderImpl();
+
+    void printInst(ZydisDecodedInstruction& inst, ZydisDecodedOperand* operands, u64 address);
+    void printInstruction(void* code, u64 address);
+    ZyanStatus decodeInstruction(ZydisDecodedInstruction& inst, ZydisDecodedOperand* operands,
+                                 void* data, u64 size = 15);
+
+private:
+    ZydisDecoder m_decoder;
+    ZydisFormatter m_formatter;
+};
+
+using Decoder = Common::Singleton<DecoderImpl>;
+
+} // namespace Common