LCOW: Fix nits from 33241
LCOW: Fix nits from 33241

Signed-off-by: John Howard <jhoward@microsoft.com>

rewritten from github.com/moby/moby 4ec9766a27ffb964cec6b8b2745725965b2644aa

tonistiigi/buildkit_poc,tonistiigi/buildkit_poc