Python3 compatibility: use open() instead of file()

For details see: https://python-future.org/compatible_idioms.html#file


Bug: chromium:948824
Change-Id: Ib06568963073621bd8edf2c8edb89bf8253d3bcb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1549169
Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60660}

third_party/binutils/download.py

@@ -27,13 +27,13 @@ BINUTILS_OUT = 'Release'
 
 
 def ReadFile(filename):
-  with file(filename, 'r') as f:
+  with open(filename, 'r') as f:
     return f.read().strip()
 
 
 def WriteFile(filename, content):
   assert not os.path.exists(filename)
-  with file(filename, 'w') as f:
+  with open(filename, 'w') as f:
     f.write(content)
     f.write('\n')