Use demo_common.sh in dlopen test script

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/test/dlopen_demo.sh b/programs/test/dlopen_demo.sh
index a6a9022..4c5384c 100755
--- a/programs/test/dlopen_demo.sh
+++ b/programs/test/dlopen_demo.sh
@@ -18,33 +18,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-set -e -u
+. "${0%/*}/../demo_common.sh"
 
-program_name="dlopen"
-program_dir="${0%/*}"
-program="$program_dir/$program_name"
+msg "Test the dynamic loading of libmbed*"
 
-if [ ! -e "$program" ]; then
-    # Look for programs in the current directory and the directories above it
-    for dir in "." ".." "../.."; do
-        program_dir="$dir/programs/test"
-        program="$program_dir/$program_name"
-        if [ -e "$program" ]; then
-            break
-        fi
-    done
-    if [ ! -e "$program" ]; then
-        echo "Could not find $program_name program"
-
-        echo "Make sure that Mbed TLS is built as a shared library." \
-             "If building out-of-tree, this script must be run" \
-             "from the project build directory."
-        exit 1
-    fi
-fi
-
-top_dir="$program_dir/../.."
-library_dir="$top_dir/library"
+program="$programs_dir/test/dlopen"
+library_dir="$root_dir/library"
 
 # ELF-based Unix-like (Linux, *BSD, Solaris, ...)
 if [ -n "${LD_LIBRARY_PATH-}" ]; then
@@ -62,6 +41,6 @@
 fi
 export DYLD_LIBRARY_PATH
 
-echo "Running dynamic loading test program: $program"
-echo "Loading libraries from: $library_dir"
+msg "Running dynamic loading test program: $program"
+msg "Loading libraries from: $library_dir"
 "$program"