Add tests to improve code coverage (#187)

* DbColumn and ReliableConnection tests

* More retry connection tests

* More tests

* Fix broken peek definition integration tests

* Fix test bug

* Add a couple batch tests

* Add some more tests

* More tests for code coverage.

* Validation and Diagnostic tests

* A few more tests

* A few mote test changes.

* Update file path tests to run on Windows only

src/Microsoft.SqlTools.ServiceLayer/sr.cs

@@ -13,7 +13,7 @@ namespace Microsoft.SqlTools.ServiceLayer
     [System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
     internal class SR
     {
-        protected SR()
+        internal SR()
         { }
 
         public static CultureInfo Culture
@@ -549,7 +549,7 @@ namespace Microsoft.SqlTools.ServiceLayer
             public const string WorkspaceServiceBufferPositionOutOfOrder = "WorkspaceServiceBufferPositionOutOfOrder";
 
 
-            private Keys()
+            internal Keys()
             { }
 
             public static CultureInfo Culture