Refactor externref related APIs of reference types feature (#971)

Currently when calling wasm_runtime_call_wasm() to invoke wasm function
with externref type argument from runtime embedder, developer needs to
use wasm_externref_obj2ref() to convert externref obj into an internal ref
index firstly, which is not convenient to developer.
To align with GC feature in which all the references passed to
wasm_runtime_call_wasm() can be object pointers directly, we change the
interface of wasm_runtime_call_wasm() to allow to pass object pointer
directly for the externref argument, and refactor the related codes, update
the related samples and the document.

core/shared/platform/windows/platform_internal.h

@@ -74,6 +74,9 @@ os_mem_decommit(void *ptr, size_t size);
 
 #define os_thread_local_attribute __declspec(thread)
 
+#define strncasecmp _strnicmp
+#define strcasecmp _stricmp
+
 #if WASM_DISABLE_HW_BOUND_CHECK == 0
 #if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64)