Gin runtime error: makeslice: cap out of range when HandleMethodNotAllowed=true and no request handler registered

Description

Gin server panics with runtime error: makeslice: cap out of range when HandleMethodNotAllowed is set to true and no handler are registered.

How to reproduce

package main

import (
    "net/http/httptest"

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

func main() {
    g := gin.New()
    g.HandleMethodNotAllowed = true

    req := httptest.NewRequest("GET", "/", nil)
    resp := httptest.NewRecorder()
    g.ServeHTTP(resp, req) // <-- Will panic
}

Expectations

No crash. I would have instead expected an HTTP error response like a 404

Actual result

panic: runtime error: makeslice: cap out of range

goroutine 1 [running]:
github.com/gin-gonic/gin.(*Engine).handleHTTPRequest(0xc00009bba0, 0xc0001ab900)
    /go/pkg/mod/github.com/gin-gonic/gin@v1.10.0/gin.go:652 +0x43f
github.com/gin-gonic/gin.(*Engine).ServeHTTP(0xc00009bba0, {0x10de2878, 0xc000406780}, 0xc0003fa5a0)
    /go/pkg/mod/github.com/gin-gonic/gin@v1.10.0/gin.go:589 +0x1b2
main.main()
    main.go:15 +0xc9

Environment

• go version: 1.22.4
• gin version (or commit ref): 1.10.0
• operating system: MacOS

Comment From: phsym

This works without issue in previous releases. For example in v1.9.1. This bug was found during our unit tests run after upgrading to v1.10.0. We had to rollback the upgrade