lttng-tools: install .expect test files with a wildcard

lttng-tools: install .expect test files with a wildcard

Otherwise, there will be failures on 32 bit hosts. Note
that the needed files are erroneously absent from upstream
release tarballs:
https://bugs.lttng.org/issues/1436
but once that is resolved, this commit will be effective.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>