testing: skip flaky TestRaiseException on windows-amd64-2012
testing: skip flaky TestRaiseException on windows-amd64-2012

This is in relation to #49681

Change-Id: I32ad8b506cf8fb0a94b15c3cc8b1eaf5af728c59
Reviewed-on: https://go-review.googlesource.com/c/go/+/378254
Run-TryBot: Patrik Nyblom <ea4dba24d4381a9f165adb5a150809dfa66d080a@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Bryan Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
Trust: Patrik Nyblom <ea4dba24d4381a9f165adb5a150809dfa66d080a@google.com>

CAFxX/go,nawawi/go,CAFxX/go,golang/go,cloudflare/go,nawawi/go,nawawi/go,golang/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,nawawi/go,cloudflare/go,cloudflare/go,CAFxX/go,cloudflare/go,CAFxX/go,nawawi/go,cloudflare/go,golang/go,golang/go,cloudflare/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,CAFxX/go,golang/go,golang/go,golang/go