cmd/link: move to cmd/newlink

In preparation for making the current linker cmd/link.
If cmd/newlink is ever completed, it can be moved back.

See golang-dev thread titled "go tool compile, etc" for background.

Change-Id: I4029580f470038240c5181a37ea4202ba971f9ef
Reviewed-on: https://go-review.googlesource.com/10286
Reviewed-by: Rob Pike <r@golang.org>

src/cmd/link/link_test.go

@@ -1,35 +0,0 @@
-// Copyright 2014 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package main
-
-import (
-	"bytes"
-	"cmd/internal/goobj"
-	"io/ioutil"
-	"testing"
-)
-
-func TestLinkHello(t *testing.T) {
-	p := &Prog{
-		GOOS:     "darwin",
-		GOARCH:   "amd64",
-		Error:    func(s string) { t.Error(s) },
-		StartSym: "_rt0_go",
-	}
-	var buf bytes.Buffer
-	p.link(&buf, "testdata/hello.6")
-	if p.NumError > 0 {
-		return
-	}
-	if p.Syms[goobj.SymID{"_rt0_go", 0}] == nil || p.Syms[goobj.SymID{"hello", 1}] == nil {
-		t.Errorf("Syms = %v, want at least [_rt0_go hello<1>]", p.Syms)
-	}
-
-	// uncomment to leave file behind for execution:
-	if false {
-		ioutil.WriteFile("a.out", buf.Bytes(), 0777)
-	}
-	checkGolden(t, buf.Bytes(), "testdata/link.hello.darwin.amd64")
-}