Code coverage improvements (#121)

These are test-only changes to improve code coverage so I'll merge directly.  Please review the commit and I'll pickup those changes in the next iteration.

* Add integration test batch file

* Exclude Linux and MacOS from Windows code coverage builds

* Enable code coverage for test driver e2e tests

* Use the windows only build for code coverage runs

src/Microsoft.SqlTools.ServiceLayer/project.json

@@ -5,6 +5,16 @@
     "debugType": "portable",
     "emitEntryPoint": true
   },
+  "configurations": {
+    "Integration": {
+      "buildOptions": {
+        "define": [
+          "WINDOWS_ONLY_BUILD"
+        ],
+        "emitEntryPoint": true
+      }
+    }
+  },
   "dependencies": {
     "Newtonsoft.Json": "9.0.1",
     "System.Data.Common": "4.1.0",