[Bug] infinite redirect with RedirectFixedPath

[ALX99]

Description

Enabling RedirectFixedPath sometimes leads to infinite redirects

How to reproduce

package main

import (
	"github.com/gin-gonic/gin"
)

func main() {
	r := gin.Default()

	r.GET("/あ", func(c *gin.Context) {
		c.JSON(200, gin.H{})
	})

	r.UnescapePathValues = false
	r.UseRawPath = true
	r.RedirectFixedPath = true
	r.Run(":8181")
}

Expectations

$ curl 'localhost:8181/%E3%81%82' -L
{}
$ curl 'localhost:8181/%e3%81%82' -L
{}
$ curl 'localhost:8181/あ' -L
{}

Actual result

$ curl 'localhost:8181/%E3%81%82' -L
{}
$ curl 'localhost:8181/%e3%81%82' -L
curl: (47) Maximum (50) redirects followed
$ curl 'localhost:8181/あ' -L
curl: (47) Maximum (50) redirects followed

Environment

go version: 1.23.0
gin version (or commit ref): v1.10.0
operating system: macOS Sequoia

[JimChenWYU]

Using /あ for comparison, but using /%e3%81%82 when redirecting, so it causes an infinite loop.

---

If using EscapedPath for comparison, responsing 404 not found

---

maybe we use req.URL.Path for redirecting, not useing req.URL.String().

[JimChenWYU]

Using /あ for comparison, but using /%e3%81%82 when redirecting, so it causes an infinite loop.

If using EscapedPath for comparison, responsing 404 not found

maybe we use req.URL.Path for redirecting, not useing req.URL.String().

ohhh... when it set Location header, it will escape url.