This test verifies that "too new" diagnostics from the stdversion analyzer
are suppressed for jsonv2 when the go version is go1.25 or later.
See golang/go#80691

-- env --
GOEXPERIMENT=jsonv2
-- flags --
-min_go_command=go1.25
-max_go_command=go1.26

-- go.mod --
module example.com

go 1.25

-- a/a.go --
//go:build goexperiment.jsonv2 || go1.27
package a

import "encoding/json/v2"

func _() {
	_ = json.Marshal // no diagnostic, see golang/go#80691
}
