Added test case for bundled gems warning with -r option.

This is for 76914d474d

tool/test_for_warn_bundled_gems/test.sh

@@ -24,6 +24,10 @@ echo "* Show warning when bundle exec with shebang's script"
 bundle exec ./test_warn_bundle_exec_shebang.rb
 echo
 
+echo "* Show warning when bundle exec with -r option"
+bundle exec ruby -rostruct -e ''
+echo
+
 echo "* Show warning with bootsnap"
 ruby test_warn_bootsnap.rb
 echo