Add MethodImplAttributes.AggressiveOptimization (dotnet/coreclr#20274)

API review: https://github.com/dotnet/corefx/issues/32628

Signed-off-by: dotnet-bot <dotnet-bot@microsoft.com>

src/System.Private.CoreLib/shared/System/Reflection/MethodImplAttributes.cs

@@ -31,6 +31,7 @@ namespace System.Reflection
         NoInlining = 0x0008,   // Method may not be inlined.
         AggressiveInlining = 0x0100,   // Method should be inlined if possible.
         NoOptimization = 0x0040,   // Method may not be optimized.
+        AggressiveOptimization = 0x0200, // Method may contain hot code and should be aggressively optimized.
 
         MaxMethodImplVal = 0xffff,
     }