Avoid rounding issues when checking Timeout values (#1700)

AsTimeout is called from the SshCommand constructor with
Timeout.InfiniteTimeSpan. In this scenario the range check should never
fail, but unfortunately it does in certain scenarios, due to a runtime
or compiler bug (as soon as optimizations are turned off the issue
miraculously disappears).

Closes #1700

Author: nikolamilekic

src/Renci.SshNet/Common/TimeSpanExtensions.cs

@@ -19,7 +19,7 @@ internal static class TimeSpanExtensions
         /// </exception>
         public static int AsTimeout(this TimeSpan timeSpan, [CallerArgumentExpression(nameof(timeSpan))] string? paramName = null)
         {
-            var timeoutInMilliseconds = timeSpan.TotalMilliseconds;
+            var timeoutInMilliseconds = Math.Round(timeSpan.TotalMilliseconds);
             return timeoutInMilliseconds is < -1d or > int.MaxValue
                        ? throw new ArgumentOutOfRangeException(paramName, "The timeout must represent a value between -1 and Int32.MaxValue milliseconds, inclusive.")
                        : (int)timeoutInMilliseconds;