Remove Assert in Method.MakeGeneric on Invalid Args

The call to mono_class_inflate_generic_method_checked will set error
when there are invalid types (e.g. typeof(void)/typeof(int*)) passed
in.  This should not be an assert, we should all to the "Invalid
generic arguments" message below.   This does loose the error returned
by mono_class_inflate_generic_method_checked but that error isn't user
friendly.  It would report be something like:

    "MVAR 1 cannot be expanded with type 0x1"

We can just report the more readable error to the user.

Note I also had to remove the "typeArguments" message from the error.
When this error is freed Mono will attempt to deallocate that value, but
since it's not a allocated value our allocator will crash (In Unity we
replace Mono's allocators with our own).

Author: scott-ferguson-unity

mono/metadata/reflection.c

@@ -2655,13 +2655,12 @@ reflection_bind_generic_method_parameters (MonoMethod *method, MonoArrayHandle t
 	tmp_context.method_inst = ginst;
 
 	inflated = mono_class_inflate_generic_method_checked (method, &tmp_context, error);
-	mono_error_assert_ok (error);
 
-	if (!mono_verifier_is_method_valid_generic_instantiation (inflated)) {
+	if (error || !inflated || !mono_verifier_is_method_valid_generic_instantiation (inflated)) {
 #if ENABLE_NETCORE
 		mono_error_set_argument (error, NULL, "Invalid generic arguments");
 #else
-		mono_error_set_argument (error, "typeArguments", "Invalid generic arguments");
+		mono_error_set_argument (error, NULL, "Invalid generic arguments");
 #endif
 		return NULL;
 	}