Test: modify whitespace.txt to verify env setup

Change-Id: Ib639c21203fc5ebde22ef99f2b8a5168b9ee6845
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1381796
Reviewed-by: Nathan Sanchez <nathanasanchez@google.com>
Commit-Queue: Cristina Huang <huangcristina@google.com>