fix(core): break reference chain to instance object

Reference caused in getContextFactory, and it stored in handlerMetadataStorage in Map, that never be purged

Author: breeeew

packages/core/helpers/context-utils.ts

@@ -89,15 +89,11 @@ export class ContextUtils {
     instance?: object,
     callback?: Function,
   ): (args: unknown[]) => ExecutionContextHost {
-    const contextFactory = (args: unknown[]) => {
-      const ctx = new ExecutionContextHost(
-        args,
-        instance && (instance.constructor as Type<unknown>),
-        callback,
-      );
+    const type = instance && (instance.constructor as Type<unknown>);
+    return (args: unknown[]) => {
+      const ctx = new ExecutionContextHost(args, type, callback);
       ctx.setType(contextType);
       return ctx;
     };
-    return contextFactory;
   }
 }