Switched to using ConditionalFact

There were some issues getting xunit to respect the -notrait option
hence we decided to simplify and use ConditionalFact

src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueTests.cs

@@ -3775,8 +3775,7 @@ .maxstack  1
         /// Reuse existing anonymous types.
         /// </summary>
         [WorkItem(825903, "DevDiv")]
-        [Fact]
-        [Trait("Require32", "true")]
+        [ConditionalFact(typeof(x86))]
         public void AnonymousTypes()
         {
             var source0 =

src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinueTests.vb

@@ -3276,8 +3276,7 @@ End Class
 ]]>.Value)
         End Sub
 
-        <Fact()>
-        <Trait("Require32", "true")>
+        <ConditionalFact(GetType(x86))>
         Public Sub AnonymousTypes()
             Dim sources0 = <compilation>
                                <file name="a.vb"><![CDATA[

src/Compilers/VisualBasic/Test/Semantic/Binding/Binder_Expressions_Tests.vb

@@ -3017,8 +3017,7 @@ End Class
         End Sub
 
         <WorkItem(1108007, "DevDiv")>
-        <Fact()>
-        <Trait("Require32", "true")>
+        <ConditionalFact(GetType(x86))>
         Public Sub Bug1108007_2()
             Dim compilation = CompilationUtils.CreateCompilationWithMscorlibAndVBRuntime(
 <compilation>
@@ -3320,8 +3319,7 @@ End Class
         End Sub
 
         <WorkItem(1108007, "DevDiv")>
-        <Fact()>
-        <Trait("Require32", "true")>
+        <ConditionalFact(GetType(x86))>
         Public Sub Bug1108007_8()
             Dim compilation = CompilationUtils.CreateCompilationWithMscorlibAndVBRuntime(
 <compilation>

src/EditorFeatures/Test/CodeFixes/ExtensionOrderingTests.cs

@@ -16,8 +16,7 @@ public class ExtensionOrderingTests
     {
         private readonly ExportProvider _exportProvider = TestExportProvider.ExportProviderWithCSharpAndVisualBasic;
 
-        [Fact]
-        [Trait("Require32", "true")]
+        [ConditionalFact(typeof(x86))]
         public void TestNoCyclesInFixProviders()
         {
             // This test will fail if a cycle is detected in the ordering of our code fix providers.

src/Tools/Source/RunTests/Program.cs

@@ -39,7 +39,7 @@ internal static int Main(string[] args)
                 ? Path.Combine(xunitPath, "xunit.console.exe")
                 : Path.Combine(xunitPath, "xunit.console.x86.exe");
 
-            var testRunner = new TestRunner(xunit, test64);
+            var testRunner = new TestRunner(xunit);
             var start = DateTime.Now;
             Console.WriteLine("Running {0} tests", list.Count);
             var result = testRunner.RunAll(list).Result;

src/Tools/Source/RunTests/TestRunner.cs

@@ -31,12 +31,10 @@ internal TestResult(bool succeeded, string assemblyName, TimeSpan elapsed, strin
         }
 
         private readonly string _xunitConsolePath;
-        private readonly bool _use64;
 
-        internal TestRunner(string xunitConsolePath, bool use64)
+        internal TestRunner(string xunitConsolePath)
         {
             _xunitConsolePath = xunitConsolePath;
-            _use64 = use64;
         }
 
         internal async Task<bool> RunAll(IEnumerable<string> assemblyList)
@@ -108,14 +106,10 @@ private async Task<TestResult> RunTest(string assemblyPath)
         {
             var assemblyName = Path.GetFileName(assemblyPath);
             var resultsPath = Path.Combine(Path.GetDirectoryName(assemblyPath), Path.ChangeExtension(assemblyName, ".html"));
+            DeleteFile(resultsPath);
+
             var builder = new StringBuilder();
             builder.AppendFormat(@"""{0}""", assemblyPath);
-
-            if (_use64)
-            {
-                builder.Append(@" -notrait ""Require32=true""");
-            }
-
             builder.AppendFormat(@" -html ""{0}""", resultsPath);
             builder.Append(" -noshadow");
 
@@ -163,5 +157,20 @@ private async Task<TestResult> RunTest(string assemblyPath)
 
             return new TestResult(processOutput.ExitCode == 0, assemblyName, span, errorOutput);
         }
+
+        private static void DeleteFile(string filePath)
+        {
+            try
+            {
+                if (File.Exists(filePath))
+                {
+                    File.Delete(filePath);
+                }
+            }
+            catch
+            {
+                // Ignore
+            }
+        }
     }
 }