test: replace CRLF by LF in a fixture

test/fixtures/test-error-first-line-offset.js is used in the
test/sequential/test-module-loading.js, but the line break type
is insignificant. It can be replaced for consistency.

PR-URL: #14437
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>

test/fixtures/test-error-first-line-offset.js

@@ -1 +1 @@
-error
+error