Make symbolic execs preferable in minimization process

[sofurihafe]

Description

After some discussions it was decided to prioritize symbolic executions over fuzzed ones. Now, priority is based on source priority (symbolic is preferable), number of useful lines (more is preferable), and exec id.
For instance, if there are two identical executions differing only by their source, the one from symbolic engine will be preferable in minimization.
This is the second attempt of pull854.

Fixes # (1504)

Type of Change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Regression and integration tests

Added a new test testPriority1 in MinimizationGreedyEssentialTest.

Automated Testing

utbot-samples, plus testPriorityTest1.

Manual Scenario

Generate a test for max method in IntExamples sample. Verify that there are two tests sourcing from symbolic engine in the generated test.

[CaelmBleidd]

After some discussions it was decided to prioritize symbolic executions over fuzzed ones.

Why? I remember the last discussion of it with Dmitry Timofeev and @sergeypospelov, and they were against this solution because of many reasons. As for me, the most important ones were described by Dmitry in his first attempt. I don't see any of the persons responsible for the minimization part or people who discussed it back then here in reviewers or in the issue discussion, so, the obvious question -- was has changed since that that moment, and what are the answers on Dmitry's (and mine, since we discussed it with him as well) concerns?