Convert most tools service tests to nunit (#1037)

* Remove xunit dependency from testdriver

* swap expected/actual as needed

* Convert Test.Common to nunit

* port hosting unit tests to nunit

* port batchparser integration tests to nunit

* port testdriver.tests to nunit

* fix target to copy dependency

* port servicelayer unittests to nunit

* more unit test fixes

* port integration tests to nunit

* fix test method type

* try using latest windows build for PRs

* reduce test memory use

test/Microsoft.SqlTools.ServiceLayer.UnitTests/Utility/SrTests.cs

@@ -4,7 +4,7 @@
 //
 
 using System.Globalization;
-using Xunit;
+using NUnit.Framework;
 
 using ServiceLayerSr = Microsoft.SqlTools.ServiceLayer.SR;
 
@@ -15,7 +15,7 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.Utility
         /// <summary>
         /// Add and remove and item in a LongList
         /// </summary>
-        [Fact]
+        [Test]
         public void SrPropertiesTest()
         {
             ServiceLayerSr.Culture = CultureInfo.CurrentCulture;