[Tizen 8.0 Migration][Service] Fix exception and change dummyTimer's interval

[Tizen 8.0 Migration][Service] Fix exception and change dummyTimer's interval

1)
When the app has resumed If the service app has no onRequest function,
JS exception can be raised. So, undefined check is necessary.

2)
Because UvTaskRunner has 500ms interval, 100ms timer is not meaningful
in Node application.

Reference:
https://review.tizen.org/gerrit/#/c/platform/framework/web/wrtjs/+/293070/

Change-Id: Id94e561e1c1e1c516c8c9ba82d664f83e2d6f404
Signed-off-by: DongHyun Song <dh81.song@samsung.com>
(cherry picked from commit 4ff972858c6fef14074e2d6ae797ee56a7ad8536)