Rollback registry key state

* `PsiInvalidElementAccessException` -> `IllegalArgumentException`

* fix `myPsiFile` not null verification

* remove code duplication, adaptation of `HTMLTextPainter` for easy to-HTML from context transformation
* resolve file/expression/statement context from Psi instead of lexer

spam.eggs.ham may be resolved to
"spam/eggs.py#def ham"
But empty folder "spam/eggs/" may go before "eggs.py" and break resolve process.

We exclude folders without of python files from test process.

[groovy] binding variables don't have declarations and hence no comments to search injection language (EA-112678)

`GrBindingVariable#getTextRange` returns `null`, because it's a light element.