JS: Add callback type tracking test

Author: asgerf

javascript/ql/test/library-tests/TypeTracking/ClassStyle.expected

@@ -38,6 +38,7 @@ test_Connection
 | tst.js:112:10:112:14 | obj.x |
 | tst.js:114:1:114:28 | getX({  ... on() }) |
 | tst.js:114:11:114:25 | getConnection() |
+| tst.js:118:12:118:26 | getConnection() |
 | tst_conflict.js:6:38:6:77 | api.cha ... ction() |
 test_DataCallback
 | client.js:3:28:3:34 | x => {} |

javascript/ql/test/library-tests/TypeTracking/PredicateStyle.expected

@@ -40,6 +40,7 @@ connection
 | type tracker without call steps | tst.js:108:8:108:22 | getConnection() |
 | type tracker without call steps | tst.js:114:1:114:28 | getX({  ... on() }) |
 | type tracker without call steps | tst.js:114:11:114:25 | getConnection() |
+| type tracker without call steps | tst.js:118:12:118:26 | getConnection() |
 | type tracker without call steps | tst_conflict.js:6:38:6:77 | api.cha ... ction() |
 | type tracker without call steps with property MyApplication.namespace.connection | file://:0:0:0:0 | global access path |
 | type tracker without call steps with property conflict | tst.js:63:3:63:25 | MyAppli ... mespace |

javascript/ql/test/library-tests/TypeTracking/tst.js

@@ -113,3 +113,15 @@ function getX(obj) {
 }
 getX({ x: getConnection() });
 getX({ x: somethingElse() });
+
+function makeConnectionAsync(callback) {
+  callback(getConnection());
+}
+makeConnectionAsync(conn => {});
+makeConnectionAsync(); // suppress single-call precision gains
+
+function makeConnectionAsync2(callback) {
+  makeConnectionAsync(callback);
+}
+makeConnectionAsync2(conn => {});
+makeConnectionAsync2(); // suppress single-call precision gains