Avoid reporting CA1859 for properties with setter more accessible than getter

[Alex-Sob]

This PR fixes #50957

Issue

'CA1859: Use concrete types when possible for improved performance' rule is reported for properties with setter more accessible than getter, for example:

public class C
{
    // CA1859: Change type of property 'Property' from 'ITest' to 'Test' for improved performance
    public ITest Property { private get; set; } = new Test();

    void M()
    {
        Property.M();
    }
}

public interface ITest
{
    void M();
}

public class Test : ITest
{
    public void M() { }
}

While properties with setter that is more accessible than getter should probably be avoided, they are legal in C# and the analyzer should avoid reporting CA1859 in such cases.

Changes

• Fixed UseConcreteTypeAnalyzer to avoid report CA1859 if a property has setter that is more accessible than getter.

• Removed bool setter parameter from UseConcreteTypeAnalyzer.Collector.CanUpgrade method since it's only used with setter: false.

• Added [StringSyntax("C#-test")] attribute to helper methods in UseConcreteTypeTests class that run a test. This enables syntax highlighting to all tests in that class.

  In [Proposal] Analyzer test readability/performance improvements #50342 I also suggested to add a helper method to Test class itself so that [StringSyntax] attribute can be applied in only in one place. It could be used instead of creating local helpers in test classes.

• Added a unit test.