Read StandardOutput in a smart way to avoid infinite loops (#830), #828

* Minor fix

Potential fix for SynchronousProcessOutputLoggerWithDiagnoser infinite loop.
Added time in Execute, detected freeze during UnitTest.

* Adding timeout to basestream read.

* Stream doesn't support timeout.

* Enhancing ProcessInput

* Minor tweak.

Disabling Executor timeout in Toolchains.
Adjusting While loop and comments on Process

src/BenchmarkDotNet/Loggers/SynchronousProcessOutputLoggerWithDiagnoser.cs

@@ -38,22 +38,27 @@ public SynchronousProcessOutputLoggerWithDiagnoser(ILogger logger, Process proce
         internal void ProcessInput()
         {
             string line;
-            while ((line = process.StandardOutput.ReadLine()) != null)
-            {
-                logger.WriteLine(LogKind.Default, line);
 
-                if (string.IsNullOrEmpty(line))
-                    continue;
+            // Peek -1 or 0 can indicate internal error.
+            while (!process.StandardOutput.EndOfStream && process.StandardOutput.Peek() > 0)
+            {
+                // ReadLine() can actually return string.Empty and null as valid values.
+                line = process.StandardOutput.ReadLine();
 
-                if (!line.StartsWith("//"))
-                    LinesWithResults.Add(line);
-                else if (Engine.Signals.TryGetSignal(line, out var signal))
+                if (!string.IsNullOrEmpty(line)) // Skip bad data.
                 {
-                    diagnoser?.Handle(signal, diagnoserActionParameters);
-                    process.StandardInput.WriteLine(Engine.Signals.Acknowledgment);
+                    logger.WriteLine(LogKind.Default, line);
+
+                    if (!line.StartsWith("//"))
+                    { LinesWithResults.Add(line); }
+                    else if (Engine.Signals.TryGetSignal(line, out var signal))
+                    {
+                        diagnoser?.Handle(signal, diagnoserActionParameters);
+                        process.StandardInput.WriteLine(Engine.Signals.Acknowledgment);
+                    }
+                    else
+                    { LinesWithExtraOutput.Add(line); }
                 }
-                else
-                    LinesWithExtraOutput.Add(line);
             }
         }
     }