tests/run-tests: Replace == by -eq when comparing rc

The use of == with test seems to cause problems when comparing the
return code in line 20. Lets use -eq instead.

Change-Id: I92905770f3a96a632a51858952a82180303d6c05
Related: OS#3376

tests/run-tests

@@ -17,7 +17,7 @@ for T in $TESTS; do
 	rm $TMP
 	./$T > $TMP
 	diff -u $EXPOUT $TMP
-	if [ $? == 0 ]; then
+	if [ $? -eq 0 ]; then
 		echo "Test $T passed"
 	else
 		echo "Test $T FAILED!"