tests: remove carriage return when using diff

tests: remove carriage return when using diff

Carriage return are a problem when running tests on cross execution
platform such as Windows. This only happen when diffing text generated
on Windows and text from a linux file.

The removal of mid-sentence '\r' is not a problem here since we do not
expect bt to generate this kind of string.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: I107c5487bf3aa0f5cbd1fdfd1e948ee93f830d2f
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1521
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>
Tested-by: jenkins <jenkins@lttng.org>