fix #620, infer the input files from sources

test/codegen_expected/language/regress_18535_test.js

Index: test/codegen_expected/language/regress_18535_test.js
diff --git a/test/codegen_expected/language/regress_18535_test.js b/test/codegen_expected/language/regress_18535_test.js
index ce55af772b186f2fd8e14bd0cf053037b5ce7582..0c6a6854ae66ffc3bb4d224622bd6d0fb857cb23 100644
--- a/test/codegen_expected/language/regress_18535_test.js
+++ b/test/codegen_expected/language/regress_18535_test.js
@@ -1,17 +1 @@
-dart_library.library('language/regress_18535_test', null, /* Imports */[
-  'dart_sdk'
-], function load__regress_18535_test(exports, dart_sdk) {
-  'use strict';
-  const core = dart_sdk.core;
-  const mirrors = dart_sdk.mirrors;
-  const dart = dart_sdk.dart;
-  const dartx = dart_sdk.dartx;
-  const regress_18535_test = Object.create(null);
-  let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [])))();
-  regress_18535_test.main = function() {
-    core.print(mirrors.currentMirrorSystem().libraries);
-  };
-  dart.fn(regress_18535_test.main, VoidTovoid());
-  // Exports:
-  exports.regress_18535_test = regress_18535_test;
-});
+//FAILED TO COMPILE