ninja&make/mac: Convert .strings files to UTF-16LE, not just UTF-16.

test/mac/gyptest-app.py

Index: test/mac/gyptest-app.py
===================================================================
--- test/mac/gyptest-app.py	(revision 1703)
+++ test/mac/gyptest-app.py	(working copy)
@@ -42,9 +42,12 @@
   test.must_not_contain(info_plist, '${MACOSX_DEPLOYMENT_TARGET}');
 
   # Resources
-  test.built_file_must_exist(
+  strings = test.built_file_path(
       'Test App Gyp.app/Contents/Resources/English.lproj/InfoPlist.strings',
       chdir='app-bundle')
+  test.built_file_must_exist(strings)
+  test.must_contain(strings, '\xff\xfe' + '/* Localized'.encode('utf-16le'))
+
   test.built_file_must_exist(
       'Test App Gyp.app/Contents/Resources/English.lproj/MainMenu.nib',
       chdir='app-bundle')