add -O1 to debug docker builds

I've been failing to repro the attached bug locally,
but I did notice that we're missing an -O1 like we
usually add to Debug bot builds.

Bug: skia:9793, skia:9664
Change-Id: If30ccfd55bad3e49862d453a754ed9fcbed9bbde
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/269938
Auto-Submit: Mike Klein <mtklein@google.com>
Commit-Queue: Weston Tracey <westont@google.com>
Reviewed-by: Weston Tracey <westont@google.com>
4 files changed