debug/pe: add IMAGE_FILE_MACHINE_ARM64

Fixes #20849

Change-Id: If2a330185aa7e95eb84dccdbc4c7f3e9b970cca1
Reviewed-on: https://go-review.googlesource.com/117056Reviewed-by: Matti Moell <matti.moell@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/debug/pe/pe.go

@@ -91,6 +91,7 @@ const (
 	IMAGE_FILE_MACHINE_AM33      = 0x1d3
 	IMAGE_FILE_MACHINE_AMD64     = 0x8664
 	IMAGE_FILE_MACHINE_ARM       = 0x1c0
+	IMAGE_FILE_MACHINE_ARM64     = 0xaa64
 	IMAGE_FILE_MACHINE_EBC       = 0xebc
 	IMAGE_FILE_MACHINE_I386      = 0x14c
 	IMAGE_FILE_MACHINE_IA64      = 0x200