chore: Embed unit test data (#1812)

* Embed unit test data

* Add testdata

Co-authored-by: anqiansong <anqiansong@bytedance.com>

tools/goctl/api/gogen/testdata/invalid_api_file.api

@@ -0,0 +1,14 @@
+type Request struct {
+    Name string `path:"name,options=you|me"`
+}
+
+type Response struct {
+    Message string `json:"message"`
+}
+
+service A-api
+    @server(
+        handler: GreetHandler
+    )
+    get /greet/from/:name(Request) returns (Response)
+}