Print process output to console instead of results file

In certain error cases, like if xunit crashes, it may not produce a test results file.  Instead of writing the process output to the test results xml file, which could be improperly interpreted as xml, write it to the console.  Also, remove add Process.Start call in case of failed xunit process.

src/Tools/Source/RunTests/TestRunner.cs

@@ -131,8 +131,10 @@ private async Task<TestResult> RunTest(string assemblyPath, CancellationToken ca
 
             if (processOutput.ExitCode != 0)
             {
-                // On occasion we get a non-0 output but no actual data in the result file.  Switch to output in this 
-                // case.
+                // On occasion we get a non-0 output but no actual data in the result file.  The could happen
+                // if xunit manages to crash when running a unit test (a stack overflow could cause this, for instance).
+                // To avoid losing information, write the process output to the console.  In addition, delete the results
+                // file to avoid issues with any tool attempting to interpret the (potentially malformed) text.
                 var all = string.Empty;
                 try
                 {
@@ -143,10 +145,14 @@ private async Task<TestResult> RunTest(string assemblyPath, CancellationToken ca
                     // Happens if xunit didn't produce a log file
                 }
 
-                if (all.Length == 0)
+                bool noResultsData = (all.Length == 0);
+                if (noResultsData)
                 {
                     var output = processOutput.OutputLines.Concat(processOutput.ErrorLines).ToArray();
-                    File.WriteAllLines(resultsPath, output);
+                    Console.Write(output);
+
+                    // Delete the output file.
+                    File.Delete(resultsPath);
                 }
 
                 errorOutput = processOutput.ErrorLines.Any()
@@ -156,8 +162,13 @@ private async Task<TestResult> RunTest(string assemblyPath, CancellationToken ca
                 errorOutput = string.Format("Command: {0} {1}", _xunitConsolePath, builder.ToString())
                     + Environment.NewLine
                     + errorOutput;
-
-                Process.Start(resultsPath);
+                    
+                // If the results are html, use Process.Start to open in the browser.
+                
+                if (_useHtml && !noResultsData)
+                {
+                    Process.Start(resultsPath);
+                }
             }
 
             return new TestResult(processOutput.ExitCode == 0, assemblyName, span, errorOutput);