Address feedback: Remove conditional compilation blocks, delete documentation and samples

Co-authored-by: mattleibow <1096616+mattleibow@users.noreply.github.com>

Author: Copilot

README.md

@@ -148,15 +148,6 @@ Other parameters can be overrided as well if needed.
 
 Currently we support **xunit v2**, **xunit v3**, and **NUnit** test assemblies but the `Microsoft.DotNet.XHarness.Tests.Runners` supports implementation of custom runner too.
 
-### xunit Version Support
-
-XHarness supports both xunit v2 and the newer xunit v3:
-
-- **xunit v2**: `Microsoft.DotNet.XHarness.TestRunners.Xunit` (stable, recommended for production)
-- **xunit v3**: `Microsoft.DotNet.XHarness.TestRunners.Xunit.v3` (stable, latest xunit architecture)
-
-For guidance on choosing between versions, see the [xunit Version Selection Guide](docs/XunitVersionSelection.md).
-
 ## Development instructions
 When working on XHarness, there are couple of neat hacks that can improve the inner loop.
 The repository can either be built using regular .NET, assuming you have new enough version:

docs/XunitVersionSelection.md

@@ -13,11 +13,7 @@ public abstract class AndroidApplicationEntryPoint : AndroidApplicationEntryPoin
 
     protected override TestRunner GetTestRunner(LogWriter logWriter)
     {
-#if USE_XUNIT_V3
-        var runner = new XUnitTestRunner(logWriter);
-#else
         var runner = new XUnitTestRunner(logWriter) { MaxParallelThreads = MaxParallelThreads };
-#endif
         ConfigureRunnerFilters(runner, ApplicationOptions.Current);
         return runner;
     }

samples/xunit-v3-sample/Program.cs

@@ -28,9 +28,7 @@ public abstract class WasmApplicationEntryPoint : WasmApplicationEntryPointBase
     protected override TestRunner GetTestRunner(LogWriter logWriter)
     {
 #if USE_XUNIT_V3
-        var runner = new XUnitTestRunner(logWriter);
-        ConfigureRunnerFilters(runner, ApplicationOptions.Current);
-        return runner;
+        throw new NotSupportedException("xunit v3 is not supported for WASM applications.");
 #else
         XunitTestRunnerBase runner = IsThreadless
             ? new ThreadlessXunitTestRunner(logWriter)

samples/xunit-v3-sample/README.md

@@ -11,11 +11,7 @@ public abstract class iOSApplicationEntryPoint : iOSApplicationEntryPointBase
 {
     protected override TestRunner GetTestRunner(LogWriter logWriter)
     {
-#if USE_XUNIT_V3
-        var runner = new XUnitTestRunner(logWriter);
-#else
         var runner = new XUnitTestRunner(logWriter) { MaxParallelThreads = MaxParallelThreads };
-#endif
         ConfigureRunnerFilters(runner, ApplicationOptions.Current);
         return runner;
     }