Implement post-MVP features and native stack overflow check (#243)

Implement native thread stack overflow check
Implement post-MVP: Non-trapping float-to-int conversions
Implement post-MVP: Sign-extension operators
Enhance WASM loader checks

core/iwasm/aot/aot_runtime.h

@@ -30,6 +30,7 @@ typedef enum AOTExceptionID {
     EXCE_UNDEFINED_ELEMENT,
     EXCE_UNINITIALIZED_ELEMENT,
     EXCE_CALL_UNLINKED_IMPORT_FUNC,
+    EXCE_NATIVE_STACK_OVERFLOW,
     EXCE_NUM,
 } AOTExceptionID;