FEXCore/Allocator: Remove unused headers

Reveals some more indirect inclusions.

FEXCore/include/FEXCore/Utils/Allocator.h

@@ -5,8 +5,6 @@
 #include <FEXCore/fextl/vector.h>
 
 #include <cstdint>
-#include <functional>
-#include <optional>
 #include <sys/types.h>
 
 namespace FEXCore::Core {

FEXCore/include/FEXCore/Utils/ThreadPoolAllocator.h

@@ -1,14 +1,17 @@
 // SPDX-License-Identifier: MIT
 #pragma once
 
-#include <atomic>
 #include <FEXCore/Utils/Allocator.h>
 #include <FEXCore/Utils/LogManager.h>
 #include <FEXCore/fextl/list.h>
 
+#include <atomic>
 #include <chrono>
 #include <cstddef>
+#include <cstdint>
 #include <mutex>
+#include <optional>
+#include <type_traits>
 
 namespace FEXCore::Utils {
 /**