Incorrect "unreachable code" detection in for/when construction inside of a sub

[aldem]

This:

Works perfectly (no errors) when on file level (in or outside of a block), but gives an error when used inside of a sub, and only for die, anything else also works:

• IntelliJ Idea 2020.1.1, Win10
• Perl Plugin 2020.1, perl support level set to 5.16

[aldem]

And a bit more, this time with return inside of when:

Seems that using of return/die anywhere (but within a sub only) triggers this behavior.

[hurricup]

Additionally we need to control when/default outside the topicalizer