Remove file name from File C++ structure. It is not used.

runtime/bin/file_macos.cc

Index: runtime/bin/file_macos.cc
diff --git a/runtime/bin/file_macos.cc b/runtime/bin/file_macos.cc
index 835b441184fcf4b0d71c3243fecacb86b8da32c7..09138cff1626fb4392bdeaa4652e06366e157412 100644
--- a/runtime/bin/file_macos.cc
+++ b/runtime/bin/file_macos.cc
@@ -126,13 +126,13 @@ File* File::Open(const char* name, FileOpenMode mode) {
       return NULL;
     }
   }
-  return new File(name, new FileHandle(fd));
+  return new File(new FileHandle(fd));
 }
 
 
 File* File::OpenStdio(int fd) {
   if (fd < 0 || 2 < fd) return NULL;
-  return new File(NULL, new FileHandle(fd));
+  return new File(new FileHandle(fd));
 }