Catch TimeoutException in WasmExecutor to restore pre-async-refactor … (#3133)

* Catch TimeoutException in WasmExecutor to restore pre-async-refactor behavior

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Update src/BenchmarkDotNet/Toolchains/MonoWasm/WasmExecutor.cs

Co-authored-by: Tim Cassell <cassell.timothy@gmail.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Tim Cassell <cassell.timothy@gmail.com>

Author: 3 people

src/BenchmarkDotNet/Toolchains/MonoWasm/WasmExecutor.cs

@@ -209,19 +209,28 @@ private static async ValueTask<ExecuteResult> Execute(Process process, Benchmark
                     process.TrySetAffinity(benchmarkCase.Job.Environment.Affinity, logger);
                 }
 
+                try
+                {
 #pragma warning disable CA2016 // Forward the 'CancellationToken' parameter to methods
-                await broker.ProcessData(cancellationToken)
-                    .AsTask()
-                    .WaitAsync(TimeSpan.FromMinutes(wasmRuntime.ProcessTimeoutMinutes)).ConfigureAwait(false);
+                    await broker.ProcessData(cancellationToken)
+                        .AsTask()
+                        .WaitAsync(TimeSpan.FromMinutes(wasmRuntime.ProcessTimeoutMinutes)).ConfigureAwait(false);
 #pragma warning restore CA2016 // Forward the 'CancellationToken' parameter to methods
 
-                results = broker.Results;
-                prefixedOutput = broker.PrefixedOutput;
-
-                if (!process.WaitForExit(milliseconds: (int)ExecuteParameters.ProcessExitTimeout.TotalMilliseconds))
+                    if (!process.WaitForExit(milliseconds: (int)ExecuteParameters.ProcessExitTimeout.TotalMilliseconds))
+                    {
+                        logger.WriteLineInfo($"// The benchmarking process did not quit within {ExecuteParameters.ProcessExitTimeout.TotalSeconds} seconds, it's going to get force killed now.");
+                    }
+                }
+                catch (TimeoutException)
                 {
-                    logger.WriteLineInfo($"// The benchmarking process did not quit within {ExecuteParameters.ProcessExitTimeout.TotalSeconds} seconds, it's going to get force killed now.");
+                    // Preserve pre-async-refactor behavior: log a message and let ProcessCleanupHelper
+                    // force-kill the process tree rather than propagating the timeout to the caller.
+                    logger.WriteLineInfo($"// The benchmarking process did not finish within {wasmRuntime.ProcessTimeoutMinutes} minutes, it's going to get force killed now.");
                 }
+
+                results = broker.Results;
+                prefixedOutput = broker.PrefixedOutput;
             }
 
             return new ExecuteResult(true,