Go. Use coverage to stop fuzzing and speed up fuzzing

[egiptipavel]

Description

• Stop fuzzing after reaching 100% coverage. The remaining time is given to the next function
• Add new test only if it covers new lines
• Run all function in one process

Fixes #1806
Fixes #1810

How to test

Manual tests

Test on utbot-go/go-samples/simple/samples.go and utbot-go/go-samples/simple/supported_types.go files.

Self-check list

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• The functionality I've repaired, changed or added is covered with automated tests.
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