Fuchsia: resolve executable name, fetch environment vars

runtime/tests/vm/dart/hello_fuchsia_test.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "dart:async";
 import "dart:convert";
 import "dart:io";
 
 testAddressParse() async {
   print(new InternetAddress("1.0.2.3").rawAddress);
@@ skipping 362 matching lines @@
     }
   } catch (e) {
     // Lookup failed or connection failed.  Don't report a failure.
     print("SocketException: $e");
   } finally {
     client.close();
   }
 }
 
 Future testProcess() async {
-  Process p = await Process.start(Platform.executable, ["--version"]);
+  String exe = Platform.resolvedExecutable;
+  print("Running $exe --version");
+  Process p = await Process.start(exe, ["--version"]);
   p.stderr.transform(UTF8.decoder).listen(print);
   int code = await p.exitCode;
-  print("dart --version exited with code $code");
+  print("$exe --version exited with code $code");
 }
 
 Future testLs(String path) async {
   Stream<FileSystemEntity> stream = (new Directory(path)).list();
   await for (FileSystemEntity fse in stream) {
     print(fse.path);
   }
 }
 
+void testPlatformEnvironment() {
+  Map<String, String> env = Platform.environment;
+  for (String k in env.keys) {
+    String v = env[k];
+    print("$k = '$v'");
+  }
+}
+
 main() async {
   print("Hello, Fuchsia!");
 
   print("testAddressParse");
   await testAddressParse();
   print("testAddressParse done");
 
   print("testSimpleBind");
   await testSimpleBind();
   print("testSimpleBind done");
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   print("testGoogleHttp done");
 
   print("testGoogleHttps");
   await testGoogleHttps(null, 'pass');
   print("testGoogleHttps done");
 
   print("lsTest");
   await testLs("/");
   print("lsTest done");
 
+  print("testPlatformEnvironment");
+  testPlatformEnvironment();
+  print("testPlatformEnvironment done");
+
   print("testProcess");
   await testProcess();
   print("testProcess done");
 
   print("Goodbyte, Fuchsia!");
 }