Generated test output size should be customizable

[denis-fokin]

Description

Take a look at the next issue: #1225. We can face situations when test-generated output is too big. This leads to increase in memory use or even IDE hang. We should handle such scenarios safely and notify user about our actions.

Expected behavior

In case if a generated string with output tests exceeds 1MB we should stop test generation and provide the user with compliable and executable tests in a file less than 1MB. Additionally, we need to add a commentary in the generated file. Commentary says that the output file is shortened. The same information is supposed to be shown in the IDE log with ability for user to navigate to the settings section in order to increase the generated file size and tests number per a method under test (by default it is supposed to be 50 test methods).

Environment

See #1225

Potential alternatives

We have discussed potential alternatives and enchantments for this approach, namely a popup that will notify the user about the shortened content of the file, splitting the file in smaller pieces.

Context

See #1225