TwoWay binding calls setter on creation

[maxkatz6]

Failing tests:

[Fact]
public void TwoWay_Binding_Should_Not_Call_Setter_On_Creation()
{
    var target = new Class1();
    var source = new TestTwoWayBindingViewModel() { Value = 1 };

    target.Bind(Class1.DoubleValueProperty, new Binding(nameof(source.Value), BindingMode.TwoWay) { Source = source });

    Assert.False(source.SetterCalled); // SetterCalled is true
}

[Fact]
public void TwoWay_Binding_Should_Not_Call_Setter_On_Creation_Indexer()
{
    var target = new Class1();
    var source = new TestTwoWayBindingViewModel() { [0] = 1 };

    target.Bind(Class1.DoubleValueProperty, new Binding("[0]", BindingMode.TwoWay) { Source = source });

    Assert.False(source.SetterCalled); // SetterCalled is true
}

Both "Class1" and "TestTwoWayBindingViewModel" exist in AvaloniaObjectTests_Binding test class.

[maxkatz6]

It doesn't call setter if property has default value.
Because of that existing TwoWay_Binding_Should_Not_Call_Setter_On_Creation and TwoWay_Binding_Should_Not_Call_Setter_On_Creation_Indexer tests passing.

[maxkatz6]

Can't be reproduced anymore. Added tests in related PR #7786