Add vue-ts-plugin-based test.

Based on the same test style as the ng-ts-plugin-based tests.

Author: sandersn

tests/cases/fourslash/server/vueProxy1.ts

@@ -0,0 +1,44 @@
+/// <reference path="../fourslash.ts"/>
+
+// @Filename: tsconfig.json
+//// {
+////     "compilerOptions": {
+////         "allowNonTsExtensions": true,
+////         "plugins": [
+////             { "name": "mock-vue" }
+////         ]
+////     },
+////     "files": ["a.vue"]
+//// }
+
+// Note: This test does *not* implement the correct vue transformation.
+// So it's other.data.property, not other.property or other.$data.property
+// @Filename: other.vue
+////<template>
+////</template>
+////<script>
+////export default {
+////    data: { property: "Example" }
+////}
+////</script>
+////<style>
+////</style>
+
+
+// @Filename: a.vue
+////<template>
+////</template>
+////<script>
+////import other from './other.vue'
+//// other.data.property/**/
+////export default {
+////    data: { greeting: "Hello" }
+////}
+////</script>
+////<style>
+////</style>
+
+// LS shouldn't crash/fail if a plugin fails to init correctly
+goTo.marker();
+verify.quickInfoIs('(property) property: string');
+verify.numberOfErrorsInCurrentFile(0);