Changing test page loading type in utc_blink_ewk_view_screenshot_contents_get* tests

Changing test page loading type in utc_blink_ewk_view_screenshot_contents_get* tests

Instead of google.com, static html page code will be loaded.
The reason behind this change is that sometimes test failed
because of connection problems, for instance when a script rebooted
device and did not manage to establish internet connection before
executing the test.

Bug: http://107.108.218.239/bugzilla/show_bug.cgi?id=10624
Reviewed by: Antonio Gomes, Janusz Majnert, Piotr Tworek

Change-Id: Ideca7340cf8a196d98bf8236ee58a49800f7010e
Signed-off-by: Lukasz Krok <l.krok@samsung.com>