Add collector test for every SDK shipped with project templates #686

public class TestSDK16_2_0 : CollectorsTests
{
      TestSDK16_2_0 ()
      {
          TestSDKVersion = "16.2.0";
      }

      // override with custom assertion if needed for instance for bug https://github.com/microsoft/vstest/pull/2221
}
....
public class TestSDKPreview : CollectorsTests
{
       TestSDKPreview ()
      {
          TestSDKVersion = "16.5.0-preview-20200110-02";
      }

      // override with custom assertion if needed
}

public abstract class CollectorsTests : BaseTest
{
       public string TestSDKVersion {get;set;}

       protected virtual void Assertions()
       {
            ....
       }

       [Fact]
       public void TestXYZ()
       {
             ....
             UpdateTestSDK(SDKVersion);
             ....
       }
}