Test generation results are eliminated after cancel

[alisevych]

Description

All test generation results are eliminated after cancel

Steps to reproduce

1. Test generation is started for several classes.
2. Wait Progress bar to show that generation for 2nd / 3rd class has been already started.
3. Cancel is clicked.

Expected result

Test classes should be created - for those classes that were processed before cancellation.

Actual result

No test classes are produced. No notification is shown.

Visual proofs

Environment

Windows 10 Pro
IntelliJ IDEA 2022.1.4 / 2022.2.3
UnitTestBot version - reproducing on different builds from main, for example

Additional context

Originally posted by @alisevych in #1187 (comment)

[alisevych]

@denis-fokin Please advise on the expected behavior: should already performed executions be saved as the resulting test classes?