Expose MethodImplOptions.AggressiveOptimization

Part of fix for https://github.com/dotnet/corefx/issues/32235
Depends on dotnet/coreclr#20009
API review: https://github.com/dotnet/corefx/issues/32235

src/System.Runtime/ref/System.Runtime.cs

@@ -6634,6 +6634,7 @@ public MethodImplAttribute(System.Runtime.CompilerServices.MethodImplOptions met
     public enum MethodImplOptions
     {
         AggressiveInlining = 256,
+        AggressiveOptimization = 512,
         ForwardRef = 16,
         InternalCall = 4096,
         NoInlining = 8,

src/System.Runtime/tests/System/Runtime/CompilerServices/MethodImplAttributeTests.cs

@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Reflection;
+using Xunit;
+
+namespace System.Runtime.CompilerServices.Tests
+{
+    public static class MethodImplAttributeTests
+    {
+        [Fact]
+        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
+        public static void AggressiveOptimizationTest()
+        {
+            Assert.Equal(
+                MethodImplOptions.AggressiveOptimization,
+                MethodBase.GetCurrentMethod().GetCustomAttribute<MethodImplAttribute>().Value);
+        }
+    }
+}