JS: Add test for API graph through spread args

Author: asgerf

javascript/ql/test/ApiGraphs/spread/VerifyAssertions.expected

@@ -0,0 +1,2 @@
+| tst.js:15:14:15:101 | /* def= ... r(0) */ | use moduleImport("something").getMember("exports").getMember("m2") has no outgoing edge labelled getParameter(0); it does have outgoing edges labelled getReceiver(), getReturn(). |
+| tst.js:16:14:16:101 | /* def= ... r(1) */ | use moduleImport("something").getMember("exports").getMember("m2") has no outgoing edge labelled getParameter(1); it does have outgoing edges labelled getReceiver(), getReturn(). |

javascript/ql/test/ApiGraphs/spread/tst.js

@@ -9,3 +9,12 @@ function f() {
 lib.m1({
     ...f()
 })
+
+function getArgs() {
+    return [
+        'x', /* def=moduleImport("something").getMember("exports").getMember("m2").getParameter(0) */
+        'y', /* def=moduleImport("something").getMember("exports").getMember("m2").getParameter(1) */
+    ]
+}
+
+lib.m2(...getArgs());