always empty options.doc and options.win

lib/single-file/single-file-core.js

@@ -177,9 +177,9 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 			this.pendingPromises = this.executeStage(REPLACE_DATA_STAGE);
 			if (this.options.doc) {
 				docUtil.postProcessDoc(this.options.doc, this.options);
-				this.options.doc = null;
-				this.options.win = null;
 			}
+			this.options.doc = null;
+			this.options.win = null;
 		}
 
 		async run() {