fix(@schematics/angular): incorrect exclude path for test.ts

Closes #11829

Author: alan-agius4

packages/schematics/angular/application/files/root/tsconfig.app.json

@@ -5,7 +5,7 @@
     "types": []
   },
   "exclude": [
-    "src/test.ts",
+    "test.ts",
     "**/*.spec.ts"
   ]<% if (experimentalIvy) { %>,
   "angularCompilerOptions": {