Fix File:copy FD leak, and add file-closes to some tests.

runtime/bin/file_linux.cc

 // Copyright (c) 2012, 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.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/file.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 247 matching lines @@
       uint8_t buffer[kBufferSize];
       while ((result = TEMP_FAILURE_RETRY(
           read(old_fd, buffer, kBufferSize))) > 0) {
         int wrote = TEMP_FAILURE_RETRY(write(new_fd, buffer, result));
         if (wrote != result) {
           result = -1;
           break;
         }
       }
     }
+    int e = errno;
+    VOID_TEMP_FAILURE_RETRY(close(old_fd));
+    VOID_TEMP_FAILURE_RETRY(close(new_fd));
     if (result < 0) {
-      int e = errno;
-      VOID_TEMP_FAILURE_RETRY(close(old_fd));
-      VOID_TEMP_FAILURE_RETRY(close(new_fd));
       VOID_NO_RETRY_EXPECTED(unlink(new_path));
       errno = e;
       return false;
     }
     return true;
   } else if (type == kIsDirectory) {
     errno = EISDIR;
   } else {
     errno = ENOENT;
   }
@@ skipping 133 matching lines @@
   return (file_1_info.st_ino == file_2_info.st_ino &&
           file_1_info.st_dev == file_2_info.st_dev) ?
       File::kIdentical :
       File::kDifferent;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)