VM: Re-format to use at most one newline between functions

runtime/bin/directory.h

Index: runtime/bin/directory.h
diff --git a/runtime/bin/directory.h b/runtime/bin/directory.h
index 433a6cca59f60efade52a78d4d1c53d65bb5745f..835a3059dc5bbbc1705a5083aea16f6cdf711db7 100644
--- a/runtime/bin/directory.h
+++ b/runtime/bin/directory.h
@@ -144,7 +144,6 @@ class DirectoryListing {
   bool follow_links_;
 };
 
-
 class AsyncDirectoryListing : public ReferenceCounted<AsyncDirectoryListing>,
                               public DirectoryListing {
  public:
@@ -189,7 +188,6 @@ class AsyncDirectoryListing : public ReferenceCounted<AsyncDirectoryListing>,
   DISALLOW_IMPLICIT_CONSTRUCTORS(AsyncDirectoryListing);
 };
 
-
 class SyncDirectoryListing : public DirectoryListing {
  public:
   SyncDirectoryListing(Dart_Handle results,
@@ -224,7 +222,6 @@ class SyncDirectoryListing : public DirectoryListing {
   DISALLOW_IMPLICIT_CONSTRUCTORS(SyncDirectoryListing);
 };
 
-
 class Directory {
  public:
   enum ExistsResult { UNKNOWN, EXISTS, DOES_NOT_EXIST };