Changes

tests/testsuite.at: fix invalid if-endif syntax

`make check` currently fails if libosmocore is configured with
`--disable-msgfile`.  The reason is that the testsuite tries to
execte a binary that does not exist.  This is happening because
the if-endif syntax is invalid and thus ignored.

Change-Id: I81e044dc0bda4674c0d0dc46118d46816712a76c