cmd/dist: skip -race w/ external linkage on windows 2008
cmd/dist: skip -race w/ external linkage on windows 2008

Add a skip for the external-linkage part of the race detector test for
elderly versions of windows, until the underlying cause for the problem
can be determined.

Updates #56904.

Change-Id: I3e8650ff66f34efefabcd6bc343d57124539901b
Reviewed-on: https://go-review.googlesource.com/c/go/+/452763
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@google.com>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Run-TryBot: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>
Auto-Submit: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>

golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go