[HTTP] Dispatching fails when same path param identifiers exist in a different order

[chamil321]

Description:
$Subject

Steps to reproduce:

import ballerina/http;

@http:ServiceConfig { basePath: "/transform" }
service transformationService on new http:Listener(9090) {

    @http:ResourceConfig {
        path:"/{aaa}/go/{bbb}"
    }
    resource function twoPathParams(http:Caller caller, http:Request req, string aaa, string bbb) {
        http:Response res = new;
        json responseJson = {xxx:aaa, yyy:bbb};
        res.setJsonPayload(<@untainted json> responseJson);
        checkpanic caller->respond(res);
    }

    @http:ResourceConfig {
        path:"{bbb}/go/{aaa}/{ccc}"
    }
    resource function threePathParams(http:Caller caller, http:Request req, string aaa, string bbb, string ccc) {
        http:Response res = new;
        json responseJson = {aaa:bbb, bbb:aaa, ccc:ccc};
        res.setJsonPayload(<@untainted json> responseJson);
        checkpanic caller->respond(res);
    }
}

Request 1

curl -v localhost:9090/transform/chamil/go/elle/gamage
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 9090 (#0)
> GET /transform/chamil/go/elle/gamage HTTP/1.1
> Host: localhost:9090
> User-Agent: curl/7.64.1
> Accept: */*
> 
< HTTP/1.1 404 Not Found
< content-type: text/plain
< content-length: 85
< server: ballerina
< date: Sat, 21 Mar 2020 18:19:08 +0530
< 
* Connection #0 to host localhost left intact
no matching resource found for path : /transform/chamil/go/elle/gamage

Request 2

 curl -v localhost:9090/transform/chamil/go/elle/gamage
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 9090 (#0)
> GET /transform/chamil/go/elle/gamage HTTP/1.1
> Host: localhost:9090
> User-Agent: curl/7.64.1
> Accept: */*
> 
< HTTP/1.1 404 Not Found
< content-type: text/plain
< content-length: 85
< server: ballerina
< date: Sat, 21 Mar 2020 18:19:04 +0530
< 
* Connection #0 to host localhost left intact
no matching resource found for path : /transform/chamil/go/elle/gamage , method : GET* Closing connection 0

Observation

If path changes as follows, it works fine
resource 1 - path:"/{aaa}/go/{bbb}"
resource 2 - path:"{aaa}/go/{bbb}/{ccc}"

HttpResourceArguments collects all path param values against the identifier. If the same identifier occurs again, then the value is getting replaced.

This condition skips getting the same param getting replaced, but that condition is incorrect.

Affected Versions:
v1.2.0