main.star: turn on structured all.bash output

It worked in https://ci.chromium.org/b/8780270441624243121!
Turn it on everywhere as the next step.

For golang/go#59990.

Change-Id: I341c86f49b41c6784b19ce546814c8d359e26e57
Reviewed-on: https://go-review.googlesource.com/c/build/+/497695
TryBot-Bypass: Dmitri Shuralyov <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Auto-Submit: Dmitri Shuralyov <[email protected]>

Author: dmitshur