[Tizen][Runtime] Add simple error page for net error.

After we have support allow-navigation on tizen, QA will test
for this. But if we do not have a net error page, QA might can
not identify whether some issues caused by crosswalk or other
net errors.
Merge pull request #2056 from CooderIan/add_simple_error_page

[Tizen][Runtime] Add simple error page for net error.