Add test precompiling dart2js.

tests/standalone/precompilation_dart2js_test.dart

Index: tests/standalone/precompilation_dart2js_test.dart
diff --git a/tests/standalone/precompilation_test.dart b/tests/standalone/precompilation_dart2js_test.dart
similarity index 80%
copy from tests/standalone/precompilation_test.dart
copy to tests/standalone/precompilation_dart2js_test.dart
index 047ac0d5c6ba00c765ba178e92a21587c0e2d889..c961a5e36c2b9ed4a92270655857621efc4cbc61 100644
--- a/tests/standalone/precompilation_test.dart
+++ b/tests/standalone/precompilation_dart2js_test.dart
@@ -43,15 +43,18 @@ main(List args) {
     return;
   }
 
+  var abs_package_root = new File(Platform.packageRoot).absolute.path;
   var dart_executable =
       Directory.current.path + Platform.pathSeparator + Platform.executable;
   Directory tmp;
   try {
     tmp = Directory.current.createTempSync("temp_precompilation_test");
-    var result = Process.runSync(
-       "${dart_executable}_no_snapshot",
-       ["--gen-precompiled-snapshot", Platform.script.path],
-       workingDirectory: tmp.path);
+    var exec = "${dart_executable}_no_snapshot";
+    var args = ["--package-root=$abs_package_root",
+                "--gen-precompiled-snapshot",
+                "${abs_package_root}compiler/src/dart2js.dart"];
+    print("$exec ${args.join(' ')}");
+    var result = Process.runSync(exec, args, workingDirectory: tmp.path);
     if (result.exitCode != 0) {
       print(result.stdout);
       print(result.stderr);
@@ -84,10 +87,10 @@ main(List args) {
 
     var ld_library_path = new String.fromEnvironment("LD_LIBRARY_PATH");
     ld_library_path = "${ld_library_path}:${tmp.path}";
-
-    result = Process.runSync(
-       "${dart_executable}",
-       ["--run-precompiled-snapshot", "ignored_script", "--hello"],
+    exec = "${dart_executable}";
+    args = ["--run-precompiled-snapshot", "ignored_script", "--version"];
+    print("LD_LIBRARY_PATH=$ld_library_path $exec ${args.join(' ')}");
+    result = Process.runSync(exec, args,
        workingDirectory: tmp.path,
        environment: {"LD_LIBRARY_PATH": ld_library_path});
     if (result.exitCode != 0) {
@@ -96,7 +99,7 @@ main(List args) {
       throw "Precompiled binary failed.";
     }
     print(result.stdout);
-    if (result.stdout != "Hello\n") {
+    if (!result.stdout.contains("Dart-to-JavaScript compiler")) {
       throw "Precompiled binary output mismatch.";
     }
   } finally {