os/signal: add missing newlines to TestTerminalSignal
os/signal: add missing newlines to TestTerminalSignal

For #37329.
For #56233.

Change-Id: Iafcddaddafd2d27fa5d535b57aaefec387f0b3f0
Reviewed-on: https://go-review.googlesource.com/c/go/+/443066
Run-TryBot: Michael Pratt <e7f1edc6d5aa9f6c8c377425db8f1a5816cbbb88@google.com>
Auto-Submit: Michael Pratt <e7f1edc6d5aa9f6c8c377425db8f1a5816cbbb88@google.com>
Reviewed-by: Bryan Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go