Revert "lib/output: add WriteBytes convenience function"
Created by: bobheadxi
Reverts sourcegraph/sourcegraph#36594, in favour of https://github.com/sourcegraph/run/pull/41
Test plan: N/A, unused function
Created by: bobheadxi
Reverts sourcegraph/sourcegraph#36594, in favour of https://github.com/sourcegraph/run/pull/41
Test plan: N/A, unused function