Add missing literal/constant properties in ICompiledExpression

As documented in https://docs.angularjs.org/api/ng/service/$parse

angularjs/angular.d.ts

@@ -910,6 +910,9 @@ declare module angular {
     interface ICompiledExpression {
         (context: any, locals?: any): any;
 
+        literal: boolean;
+        constant: boolean;
+
         // If value is not provided, undefined is gonna be used since the implementation
         // does not check the parameter. Let's force a value for consistency. If consumer
         // whants to undefine it, pass the undefined value explicitly.