build: mv cmd/vendor cmd/internal/unvendor

And update two imports in cmd/internal/objfile/disasm.go.
This makes GO15VENDOREXPERIMENT=0 ./make.bash work.
For Go 1.7 we will move it back.

Fixes #14236.

Change-Id: I429c9af4baff8496f83d113b1b03b90e309f4f48
Reviewed-on: https://go-review.googlesource.com/19384
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

misc/nacl/testzip.proto

@@ -27,6 +27,18 @@ go	src=..
 			internal
 				objfile
 					objfile.go
+				unvendor
+					golang.org
+							x
+								arch
+									arm
+										armasm
+											testdata
+													+
+									x86
+										x86asm
+											testdata
+													+
 			gofmt
 				gofmt.go
 				gofmt_test.go
@@ -35,18 +47,6 @@ go	src=..
 			newlink
 				testdata
 					+
-			vendor
-				golang.org
-						x
-							arch
-								arm
-									armasm
-										testdata
-												+
-								x86
-									x86asm
-										testdata
-												+
 		archive
 			tar
 				testdata

src/cmd/internal/objfile/disasm.go

@@ -15,8 +15,8 @@ import (
 	"strings"
 	"text/tabwriter"
 
-	"golang.org/x/arch/arm/armasm"
-	"golang.org/x/arch/x86/x86asm"
+	"cmd/internal/unvendor/golang.org/x/arch/arm/armasm"
+	"cmd/internal/unvendor/golang.org/x/arch/x86/x86asm"
 )
 
 // Disasm is a disassembler for a given File.