catch and report unexpected exceptions

[robstoll]

Platform (all, jvm, js): all Extension (none, kotlin 1.3): none

Code related feature

Currently, we only catch unexpected exceptions in:

• feature extractors
• Function0.toThrow/notToThrow

But we especially don't do it in:

• ExpectGrouping-block
• groups
• expectation-groups
• subject changer
• _logicAppend

Which means we:

• fail fast
• might miss to evaluate further expectations
• won't be able to report anything about already evaluated expectations or give more context

For instance:

expectGrouped {
   group("foo") {

      // one expectation fails
   }

  group("bar") {
    // throws unexpected exception
  }

  group("baz"){
    // no longer evaluated
  }
}

The result will be that we only see that an IllegalStateException was thrown and not a single report of Atrium

Relates to 387