When external linking, in case that the external linker generates
a code signature with a different size (e.g. as it uses a
different identifier), truncate the file after rewriting the code
signature, to make sure that no bytes after the signature (which
will invalidate the signature).
Fixes #43105.
Change-Id: I732f949fedd6de42d9f3cf6d017f7ba3f4e59e7a
Reviewed-on: https://go-review.googlesource.com/c/go/+/276693
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>