fix: fix Go formatting and flaky torch_baseimage_fallback integration test (#2817)
* fix: remove trailing whitespace in integration test harness
* fix: convert torch_baseimage_fallback test to use cog debug instead of cog build
The test was doing a real Docker build with torch==1.13.0 which failed
because pip can no longer reliably install this old package. Since the
test's purpose is to verify Dockerfile generation falls back to
nvidia/cuda (not cog-base), use cog debug to check the generated
Dockerfile text. Uses an empty local registry for deterministic behavior.