tests: Remove debug statement from tap.sh

tests: Remove debug statement from tap.sh

It looks like a debug statement got left in for commit 2a69bf1437. The
debug statement uses print, which is not necessarily a commonly
available command, and led to spurious errors on certain CI nodes.

Eg. https://ci.lttng.org/job/lttng-tools_master_slesbuild/976/babeltrace_version=stable-2.0,build=std,conf=agents,liburcu_version=master,platform=sles15sp4-amd64/consoleFull

Change-Id: If035e57489b5bf6185f73d1046bfdbd03f4a1fed
Signed-off-by: Kienan Stewart <kstewart@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>