Add Directory.systemTemp getter to replace createSystemTemp().

runtime/bin/directory.h

Index: runtime/bin/directory.h
diff --git a/runtime/bin/directory.h b/runtime/bin/directory.h
index 57302a2922182cee15d98dafbc11f1aa74ce9f64..fd78e8020a27a81b8544ac89a787b329c59ec8de 100644
--- a/runtime/bin/directory.h
+++ b/runtime/bin/directory.h
@@ -257,7 +257,8 @@ class Directory {
   static char* Current();
   static bool SetCurrent(const char* path);
   static bool Create(const char* path);
-  static char* CreateTemp(const char* const_template, bool system);
+  static char* SystemTemp();
+  static char* CreateTemp(const char* path);
   static bool Delete(const char* path, bool recursive);
   static bool Rename(const char* path, const char* new_path);