[vm] correctly create connection errors
[vm] correctly create connection errors

When sourceAddress is null, there is no bind call, so the error cannot
possibly be a bind failure.

Change-Id: Idec2aff48c436b89f9b571458d0fbce700793d33
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/110184
Commit-Queue: Zach Anderson <9f8b31e960a68dade71618f1ff6da6e23a1edfc9@google.com>
Reviewed-by: Zach Anderson <9f8b31e960a68dade71618f1ff6da6e23a1edfc9@google.com>
Auto-Submit: Tamir Duberstein <c96a05aaafbe4b3abc1841a4083a1b0f402c2ba6@google.com>

dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk