Remove inconsistent UnmanagedCallersOnly delegate construction check

src/coreclr/vm/comdelegate.cpp

@@ -2793,13 +2793,6 @@ MethodDesc* COMDelegate::GetDelegateCtor(TypeHandle delegateType, MethodDesc *pT
     // associated with the instantiation.
     BOOL fMaybeCollectibleAndStatic = FALSE;
 
-    // Do not allow static methods with [UnmanagedCallersOnlyAttribute] to be a delegate target.
-    // A method marked UnmanagedCallersOnly is special and allowing it to be delegate target will destabilize the runtime.
-    if (pTargetMethod->HasUnmanagedCallersOnlyAttribute())
-    {
-        COMPlusThrow(kNotSupportedException, W("NotSupported_UnmanagedCallersOnlyTarget"));
-    }
-
     if (isStatic)
     {
         // When this method is called and the method being considered is shared, we typically

src/libraries/System.Private.CoreLib/src/Resources/Strings.resx

@@ -3092,9 +3092,6 @@
   <data name="NotSupported_MustBeModuleBuilder" xml:space="preserve">
     <value>Module argument must be a ModuleBuilder.</value>
   </data>
-  <data name="NotSupported_UnmanagedCallersOnlyTarget" xml:space="preserve">
-    <value>Methods with UnmanagedCallersOnlyAttribute cannot be used as delegate target.</value>
-  </data>
   <data name="NotSupported_NoCodepageData" xml:space="preserve">
     <value>No data is available for encoding {0}. For information on defining a custom encoding, see the documentation for the Encoding.RegisterProvider method.</value>
   </data>

src/tests/Interop/UnmanagedCallersOnly/InvalidCallbacks.il

@@ -101,47 +101,6 @@
         ret
     }
 
-    .method public hidebysig static
-    int32 ManagedDoubleCallback (
-        int32 n
-    ) cil managed
-    {
-        .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.UnmanagedCallersOnlyAttribute::.ctor() = (
-            01 00 00 00
-        )
-        .maxstack 1
-
-        nop
-        ldarg.0
-        call int32 InvalidCSharp.CallingUnmanagedCallersOnlyDirectly::DoubleImpl(int32)
-        ret
-    }
-
-    .method private hidebysig static
-        int32 DoubleImpl (
-            int32 n
-        ) cil managed
-    {
-        .maxstack 2
-
-        nop
-        ldc.i4.2
-        ldarg.0
-        mul
-        ret
-    }
-
-    .method public hidebysig static
-    class [System.Runtime]System.Func`2<int32, int32> GetDoubleDelegate () cil managed
-    {
-        .maxstack 8
-
-        ldnull
-        ldftn int32 InvalidCSharp.CallingUnmanagedCallersOnlyDirectly::ManagedDoubleCallback(int32)
-        newobj instance void class [System.Runtime]System.Func`2<int32, int32>::.ctor(object, native int)
-        ret
-    }
-
     .method public hidebysig static pinvokeimpl("UnmanagedCallersOnlyDll" as "DoesntExist" winapi)
     int32 PInvokeMarkedWithUnmanagedCallersOnly (
         int32 n

src/tests/Interop/UnmanagedCallersOnly/UnmanagedCallersOnlyTest.cs

@@ -51,22 +51,6 @@ public static void TestUnmanagedCallersOnlyValid_ThrowException()
         Assert.Equal(-1, UnmanagedCallersOnlyDll.CallManagedProcCatchException((IntPtr)(delegate* unmanaged<int, int>)&CallbackThrows, n));
     }
 
-    [Fact]
-    public static void NegativeTest_ViaDelegate()
-    {
-        Console.WriteLine($"Running {nameof(NegativeTest_ViaDelegate)}...");
-
-        // Try invoking method directly
-        Assert.Throws<NotSupportedException>(() => { CallAsDelegate(); });
-
-        // Local function to delay exception thrown during JIT
-        void CallAsDelegate()
-        {
-            Func<int, int> invoker = CallingUnmanagedCallersOnlyDirectly.GetDoubleDelegate();
-            invoker(0);
-        }
-    }
-
     [Fact]
     public static void NegativeTest_NonStaticMethod()
     {