Implement Multi-tier JIT (#1774)

Implement 2-level Multi-tier JIT engine: tier-up from Fast JIT to LLVM JIT to
get quick cold startup by Fast JIT and better performance by gradually
switching to LLVM JIT when the LLVM JIT functions are compiled by the
backend threads.

Refer to:
https://github.com/bytecodealliance/wasm-micro-runtime/issues/1302

core/iwasm/fast-jit/jit_frontend.c

@@ -2255,6 +2255,12 @@ jit_frontend_translate_func(JitCompContext *cc)
     return basic_block_entry;
 }
 
+uint32
+jit_frontend_get_jitted_return_addr_offset()
+{
+    return (uint32)offsetof(WASMInterpFrame, jitted_return_addr);
+}
+
 #if 0
 #if WASM_ENABLE_THREAD_MGR != 0
 bool