reformat GN files

Change-Id: I2d19c4f0ff1439dcd923a3064eb3ba78432a5113
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/281043
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
29 files changed