Issue Description

With echo v3.3.8 (and probably other versions), it's possible for echo.Reverse to return nondeterministic results due to its implementation. If you define two routes that both map to the same handler function, multiple calls to echo.Reverse on the handler function can result in different outputs.

Checklist

• Dependencies installed
• No typos
• Searched existing issues and docs

Expected behaviour

Calling echo.Reverse on a handler function always results in the same output, whether that is all of the routes that map to a given handler, or the first one found.

Actual behaviour

Calling echo.Reverse on a handler function can result in different outputs each time it is called.

Steps to reproduce

Create a handler function and two routes that map to it (method is irrelevant, since echo.Reverse does not use it). Call echo.Reverse on the handler function many times in a loop and observe that the output may change. See code below as well. This happens because echo.Reverse iterates a map[string]*Route to find a match, and iterating a map in Go produces elements of the map in an arbitrary order.

Working code to debug

package main

import (
	"fmt"
	"reflect"
	"runtime"

	"github.com/labstack/echo"
)

func handler(ctxt echo.Context) error {
	return nil
}

func main() {
	ech := echo.New()
	ech.GET("/abc", handler)
	ech.GET("/xyz", handler)

	for i := 0; i < 100; i++ {
		fmt.Println(ech.Reverse(runtime.FuncForPC(reflect.ValueOf(handler).Pointer()).Name()))
	}
}

Version/commit

I am using version =3.3.8