JavaScript: Add test for FlowSteps::argumentPassing predicate.

Author: Max Schaefer

javascript/ql/test/library-tests/DataFlow/argumentPassing.expected

@@ -0,0 +1,6 @@
+| sources.js:3:1:5:6 | (functi ... \\n})(23) | sources.js:5:4:5:5 | 23 | sources.js:3:2:5:1 | functio ... x+19;\\n} | sources.js:3:11:3:11 | x |
+| tst.js:16:1:20:9 | (functi ... ("arg") | tst.js:20:4:20:8 | "arg" | tst.js:16:2:20:1 | functio ... n "";\\n} | tst.js:16:13:16:13 | a |
+| tst.js:35:1:35:7 | g(true) | tst.js:35:3:35:6 | true | tst.js:32:1:34:1 | functio ... ables\\n} | tst.js:32:12:32:12 | b |
+| tst.js:44:1:44:5 | o.m() | tst.js:44:1:44:1 | o | tst.js:39:4:41:3 | () {\\n    this;\\n  } | tst.js:39:4:39:3 | this |
+| tst.js:87:1:96:2 | (functi ... r: 0\\n}) | tst.js:92:4:96:1 | {\\n  p:  ...  r: 0\\n} | tst.js:87:2:92:1 | functio ...  + z;\\n} | tst.js:87:11:87:24 | { p: x, ...o } |
+| tst.js:98:1:103:17 | (functi ... 3, 0 ]) | tst.js:103:4:103:16 | [ 19, 23, 0 ] | tst.js:98:2:103:1 | functio ...  + z;\\n} | tst.js:98:11:98:24 | [ x, ...rest ] |

javascript/ql/test/library-tests/DataFlow/argumentPassing.ql

@@ -0,0 +1,6 @@
+import javascript
+import semmle.javascript.dataflow.internal.FlowSteps as FlowSteps
+
+from DataFlow::Node invk, DataFlow::Node arg, Function f, DataFlow::SourceNode parm
+where FlowSteps::argumentPassing(invk, arg, f, parm)
+select invk, arg, f, parm