Testing for equality using a predicate throws exception for collections

[PiotrKlecha]

Attempting to test collections for equality using a predicate that compares items fails with an exception.

The following example tests:

        [Test]
        public void UsesProvidedPredicateForItemComparison()
        {
            var expected = new[] { "yeti", "łysy", "rysiu" };
            var actual = new[] { "YETI", "Łysy", "RySiU" };

            Assert.That(actual, Is.EqualTo(expected).Using<string>((x, y) => StringUtil.StringsEqual(x, y, true)));
        }

        [Test]
        public void UsesProvidedPredicateForItemComparisonDifferentTypes()
        {
            var expected = new[] { 1, 2, 3 };
            var actual = new[] { "1", "2", "3" };

            Assert.That(actual, Is.EqualTo(expected).Using<string, int>((s, i) => i.ToString() == s));
        }

both throw an exception:
System.InvalidCastException : Unable to cast object of type 'System.String[]' to type 'System.String'.
w NUnit.Framework.Constraints.EqualityAdapter.PredicateEqualityAdapter`2.AreEqual(Object x, Object y)
w NUnit.Framework.Constraints.NUnitEqualityComparer.AreEqual(Object x, Object y, Tolerance& tolerance, Boolean topLevelComparison)
w NUnit.Framework.Constraints.EqualConstraint.ApplyTo[TActual](TActual actual)
w NUnit.Framework.Assert.That[TActual](TActual actual, IResolveConstraint expression, String message, Object[] args)
w NUnit.Framework.Assert.That[TActual](TActual actual, IResolveConstraint expression)

Similar comparisons performed using a dedicated IComparer or IEqualityComparer pass correctly.