Check for PanicSentinel in SequenceLiteralNode

[JaroslavTulach]

Pull Request Description

Fixes #7245.

The above picture shows that the vector problem reported by #7245 is fixed.

Important Notes

The fix modifies SequenceLiteralNode to recognize PanicSentinel and throw it as common in other places (like invoke function node, etc.).

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
• All code has been tested:
  • Unit tests have been written where possible.

[kustosz]

One thing to note here – a PanicSentinel should not be handleable by any in-language methods or functions. It is purely a hack to get the IDE to not panic when there's a panic. But note that it has different semantics in CLI and IDE and so cannot be a language mechanism (must be an IDE-only mechanism). I think this PR makes it possible to "escape" a sentinel sometimes? Which is bad. It should not be possible to handle a sentinel.

[JaroslavTulach]

I think this PR makes it possible to "escape" a sentinel sometimes? Which is bad.
It should not be possible to handle a sentinel.

Thank you Marcin. Rewritten to just throw in SequenceLiteralNode.

[4e6]

It's much better than wrapping it in a warning 👍

[4e6]

Don't forget to update the PR title