1.修复热启动无法拉起授权的问题

android/src/main/java/com/wxwx/flutter_alibc/FlutterAlibcHandle.java

@@ -48,16 +48,15 @@ import java.util.Map;
 public class FlutterAlibcHandle {
 
     private static FlutterAlibcHandle handle;
-    private Registrar register;
+    private static Registrar register;
 
     //第一次调用getInstance register不能为空
     public static FlutterAlibcHandle getInstance(Registrar register) {
-        if (handle == null) {
+
             synchronized (FlutterAlibcHandle.class) {
                 handle = new FlutterAlibcHandle();
-                handle.register = register;
+                FlutterAlibcHandle.register = register;
             }
-        }
         return handle;
     }