Fix reporting of CompileTimeErrorCode.PRIVATE_SETTER

The error code text is:

    The setter '{0}' is private and can't be accessed outside of the
    library that declares it.

So when instantiating this error we should only provide a single
argument.  Previously we were providing a second argument that was the
name of the type.

Change-Id: I952dec86f079b9e17e071d37895c3b38c715cf4f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/213826
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>

pkg/analyzer/lib/src/dart/resolver/property_element_resolver.dart

@@ -492,7 +492,7 @@ class PropertyElementResolver {
           _errorReporter.reportErrorForNode(
             CompileTimeErrorCode.PRIVATE_SETTER,
             propertyName,
-            [propertyName.name, typeReference.name],
+            [propertyName.name],
           );
         }
         _checkForStaticAccessToInstanceMember(propertyName, writeElement);