Mark forward delegate stubs as not having hidden arguments

Forward delegate interop stubs do not use hidden argument. The hidden argument passed to them is a random value that can lead to crash during stackwalking.

Fixes dotnet#62613

src/coreclr/vm/dllimport.cpp

@@ -784,14 +784,11 @@ class ILStubState : public StubState
         {
             // Struct marshal stubs don't actually call anything so they do not need the secrect parameter.
         }
-#ifndef HOST_64BIT
         else if (SF_IsForwardDelegateStub(m_dwStubFlags))
         {
             // Forward delegate stubs get all the context they need in 'this' so they
-            // don't use the secret parameter. Except for AMD64 where we use the secret
-            // argument to pass the real target to the stub-for-host.
+            // don't use the secret parameter.
         }
-#endif // !HOST_64BIT
         else
         {
             // All other IL stubs will need to use the secret parameter.

src/coreclr/vm/metasig.h

@@ -509,7 +509,6 @@ DEFINE_METASIG_T(IM(Str_BindingFlags_Binder_Obj_ArrObj_ArrParameterModifier_Cult
                  s g(BINDING_FLAGS) C(BINDER) j a(j) a(g(PARAMETER_MODIFIER)) C(CULTURE_INFO) a(s), j))
 DEFINE_METASIG_T(IM(Str_Type_Str_RetVoid, s C(TYPE) s, v))
 DEFINE_METASIG_T(SM(Delegate_RetIntPtr, C(DELEGATE), I))
-DEFINE_METASIG_T(SM(Delegate_RefIntPtr_RetIntPtr, C(DELEGATE) r(I), I))
 DEFINE_METASIG_T(SM(RuntimeTypeHandle_RetType, g(RT_TYPE_HANDLE), C(TYPE)))
 DEFINE_METASIG_T(SM(RuntimeTypeHandle_RetIntPtr, g(RT_TYPE_HANDLE), I))
 DEFINE_METASIG_T(SM(RuntimeMethodHandle_RetIntPtr, g(METHOD_HANDLE), I))

src/coreclr/vm/method.hpp

@@ -2606,7 +2606,7 @@ class DynamicMethodDesc : public StoredSigMethodDesc
     bool HasMDContextArg()
     {
         LIMITED_METHOD_CONTRACT;
-        return IsCLRToCOMStub() || IsPInvokeStub();
+        return IsCLRToCOMStub() || (IsPInvokeStub() && !IsDelegateStub());
     }
 
     //