Upgrade Embree to the latest official release.

Since Embree v3.13.0 supports AARCH64, switch back to the
official repo instead of using Embree-aarch64.

`thirdparty/embree/patches/godot-changes.patch` should now contain
an accurate diff of the changes done to the library.

thirdparty/embree/include/embree3/rtcore_config.h

@@ -0,0 +1,57 @@
+
+// Copyright 2009-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#define RTC_VERSION_MAJOR 3
+#define RTC_VERSION_MINOR 13
+#define RTC_VERSION_PATCH 0
+#define RTC_VERSION 31300
+#define RTC_VERSION_STRING "3.13.0"
+
+#define RTC_MAX_INSTANCE_LEVEL_COUNT 1
+
+#define EMBREE_MIN_WIDTH 0
+#define RTC_MIN_WIDTH EMBREE_MIN_WIDTH
+
+#define EMBREE_STATIC_LIB
+/* #undef EMBREE_API_NAMESPACE */
+
+#if defined(EMBREE_API_NAMESPACE)
+#  define RTC_NAMESPACE
+#  define RTC_NAMESPACE_BEGIN namespace  {
+#  define RTC_NAMESPACE_END }
+#  define RTC_NAMESPACE_USE using namespace ;
+#  define RTC_API_EXTERN_C
+#  undef EMBREE_API_NAMESPACE
+#else
+#  define RTC_NAMESPACE_BEGIN
+#  define RTC_NAMESPACE_END
+#  define RTC_NAMESPACE_USE
+#  if defined(__cplusplus)
+#    define RTC_API_EXTERN_C extern "C"
+#  else
+#    define RTC_API_EXTERN_C
+#  endif
+#endif
+
+#if defined(ISPC)
+#  define RTC_API_IMPORT extern "C" unmasked
+#  define RTC_API_EXPORT extern "C" unmasked
+#elif defined(EMBREE_STATIC_LIB)
+#  define RTC_API_IMPORT RTC_API_EXTERN_C
+#  define RTC_API_EXPORT RTC_API_EXTERN_C
+#elif defined(_WIN32)
+#  define RTC_API_IMPORT RTC_API_EXTERN_C __declspec(dllimport)
+#  define RTC_API_EXPORT RTC_API_EXTERN_C __declspec(dllexport)
+#else
+#  define RTC_API_IMPORT RTC_API_EXTERN_C
+#  define RTC_API_EXPORT RTC_API_EXTERN_C __attribute__ ((visibility ("default")))
+#endif
+
+#if defined(RTC_EXPORT_API)
+#  define RTC_API RTC_API_EXPORT
+#else
+#  define RTC_API RTC_API_IMPORT
+#endif