Autotests: Implement "single responsibility" approach for takeElementScreenshot function

[AlexeyGirin]

Now takeElementScreenshot function contains wait logic that guarantee that if rendering process was started BEFORE takeElementScreenshot function call - it waits it's end (or simply waits 1.5 secs till timeout if no any rendering).

This is violation of "single responsibility" approach and causes extra execution time for many tests.
Please remove that logic and correct all tests that illegally uses takeElementScreenshot function capability of rendering wait