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.

Author: michaeldwan

integration-tests/harness/harness.go

@@ -501,7 +501,7 @@ func (h *Harness) cmdCurl(ts *testscript.TestScript, neg bool, args []string) {
 				ts.Fatalf("curl: failed to read body file %q: %v", filename, err)
 			}
 			body = string(data)
-		} 
+		}
 	}
 
 	// Retry settings