[refactoring] Extract read leb to a separate file, share the code between loader and mini loader (#3701)

There's probably a number of other places where the bh_leb_read could be used (e.g. aot loader)
but I'm making the change as small as possible. Further refactoring can be done later.

core/shared/utils/bh_leb128.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#ifndef _BH_LEB128_H
+#define _BH_LEB128_H
+
+#include "bh_platform.h"
+
+typedef enum {
+    BH_LEB_READ_SUCCESS,
+    BH_LEB_READ_TOO_LONG,
+    BH_LEB_READ_OVERFLOW,
+    BH_LEB_READ_UNEXPECTED_END,
+} bh_leb_read_status_t;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bh_leb_read_status_t
+bh_leb_read(const uint8 *buf, const uint8 *buf_end, uint32 maxbits, bool sign,
+            uint64 *p_result, size_t *p_offset);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif