cloud-build: set HOME env variable.

Bug: 993053
Change-Id: I6069def4a063dbe7a4f8c6fe9cc5046d014e4f3c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/247046
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Joe Gregorio <jcgregorio@google.com>
2 files changed