Make test script exit code non-0 on test failures.

Tools/ci-run.sh

@@ -101,6 +101,7 @@ python runtests.py \
    $LIMITED_API \
    $EXCLUDE \
    $(if [ "$COVERAGE" == "1" ]; then echo " --coverage"; fi) \
-   $(if [ -z "$TEST_CODE_STYLE" ]; then echo " -j7 "; fi)
+   $(if [ -z "$TEST_CODE_STYLE" ]; then echo " -j7 "; fi) \
+   || exit 1
 
 ccache -s 2>/dev/null || true