JS: Add test

Author: asgerf

javascript/ql/test/query-tests/Expressions/MissingAwait/MissingAwait.expected

@@ -1,3 +1,4 @@
+| tsTest.ts:4:12:4:19 | cache[x] | Missing await. This value is always a promise. |
 | tst.js:8:9:8:13 | thing | Missing await. The value 'thing' is always a promise. |
 | tst.js:10:9:10:13 | thing | Missing await. The value 'thing' is always a promise. |
 | tst.js:12:15:12:19 | thing | Missing await. The value 'thing' is always a promise. |

javascript/ql/test/query-tests/Expressions/MissingAwait/tsTest.ts

@@ -0,0 +1,5 @@
+declare let cache: { [x: string]: Promise<any> };
+
+function deleteCache(x: string) {
+    delete cache[x]; // OK
+}

javascript/ql/test/query-tests/Expressions/MissingAwait/tsconfig.json

@@ -0,0 +1,3 @@
+{
+    "include": ["."]
+}