Update DefineMethodOverride example to target .NET 9

Co-authored-by: gewarren <[email protected]>

Author: Copilot

snippets/csharp/System.Reflection.Emit/TypeBuilder/DefineMethodOverride/Project.csproj

@@ -1,8 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <OutputType>Library</OutputType>
-    <TargetFramework>net48</TargetFramework>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
   </PropertyGroup>
 
 </Project>

snippets/csharp/System.Reflection.Emit/TypeBuilder/DefineMethodOverride/source.cs

@@ -40,9 +40,9 @@ static void Main()
         string name = "DefineMethodOverrideExample";
         AssemblyName asmName = new AssemblyName(name);
         AssemblyBuilder ab =
-            AppDomain.CurrentDomain.DefineDynamicAssembly(
-                asmName, AssemblyBuilderAccess.RunAndSave);
-        ModuleBuilder mb = ab.DefineDynamicModule(name, name + ".dll");
+            AssemblyBuilder.DefineDynamicAssembly(
+                asmName, AssemblyBuilderAccess.Run);
+        ModuleBuilder mb = ab.DefineDynamicModule(name);
 
         TypeBuilder tb =
             mb.DefineType("C", TypeAttributes.Public, typeof(A));
@@ -83,9 +83,6 @@ static void Main()
 
         Type tc = tb.CreateType();
 
-        // Save the emitted assembly, to examine with Ildasm.exe.
-        ab.Save(name + ".dll");
-
         Object test = Activator.CreateInstance(tc);
 
         MethodInfo mi = typeof(I).GetMethod("M");