message: Configure GN to use python3 to exec_script.
  Cr-Commit-Position: refs/heads/master@{#33735}
diff: @@ -11,6 +11,10 @@ import("//build/dotfile_settings.gni")
  # The location of the build configuration file.
  buildconfig = "//build/config/BUILDCONFIG.gn"
  +# The python interpreter to use by default. On Windows, this will look
  +# for python3.exe and python3.bat.
  +script_executable = "python3"
  +
  # The secondary source root is a parallel directory tree where
  # GN build files are placed when they can not be placed directly
  # in the source tree, e.g. for third party source trees.
  