Implement wasm_runtime_init_thread_env() for Windows platform by calling os_thread_env_init(): if current thread is created by developer himself but not runtime, developer should call wasm_runtime_init_thread_env() to init the thread environment before calling wasm function, and call wasm_runtime_destroy_thread_env() before thread exits.
And clear compile warnings for Windows platform, fix compile error for AliOS-Things platform
Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>