[SPARK-3192] Some scripts have 2 space indentation but other scripts have 4 space indentation.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #2104 from sarutak/SPARK-3192 and squashes the following commits:

db78419 [Kousuke Saruta] Modified indentation of spark-shell
(cherry picked from commit ded6796bf54f5c005b27135d7dec19634038a1c6)

Signed-off-by: Patrick Wendell <pwendell@gmail.com>