Ensure folder exists.

Update wasmcsproj template.

Author: timcassell

src/BenchmarkDotNet/Templates/WasmCsProj.txt

@@ -23,6 +23,7 @@
     <RunAOTCompilation>$RUN_AOT$</RunAOTCompilation>
     <PublishTrimmed>$(RunAOTCompilation)</PublishTrimmed>
     <WasmGenerateRunV8Script>true</WasmGenerateRunV8Script>
+    <ErrorOnDuplicatePublishOutputFiles>false</ErrorOnDuplicatePublishOutputFiles>
     <ValidateExecutableReferencesMatchSelfContained>false</ValidateExecutableReferencesMatchSelfContained>
     <EnableDefaultWasmAssembliesToBundle>false</EnableDefaultWasmAssembliesToBundle>
     <StartupObject>BenchmarkDotNet.Autogenerated.UniqueProgramName</StartupObject>

src/BenchmarkDotNet/Toolchains/GeneratorBase.cs

@@ -2,6 +2,7 @@
 using System.IO;
 using System.Text;
 using BenchmarkDotNet.Code;
+using BenchmarkDotNet.Extensions;
 using BenchmarkDotNet.Loggers;
 using BenchmarkDotNet.Portability;
 using BenchmarkDotNet.Running;
@@ -103,6 +104,7 @@ [PublicAPI] protected virtual void GenerateProject(BuildPartition buildPartition
         [PublicAPI] protected virtual void GenerateAppConfig(BuildPartition buildPartition, ArtifactsPaths artifactsPaths)
         {
             string sourcePath = buildPartition.AssemblyLocation + ".config";
+            artifactsPaths.AppConfigPath.EnsureFolderExists();
 
             using (var source = File.Exists(sourcePath) ? new StreamReader(File.OpenRead(sourcePath)) : TextReader.Null)
             using (var destination = new StreamWriter(File.Create(artifactsPaths.AppConfigPath), Encoding.UTF8))