Rework rendering of kt-like dump and signatures dump in order to avoid
unstable blank line between declarations of the same level:
1. No blank line for the first declaration inside the member scope of
the class.
2. Always a single blank line between each two subsequent declarations
inside the member scope of the class.
This change allows to revert adding `WITH_STDLIB` directive
to tests which happened at `a9343aeb`.
Co-authored-by: Alexander Udalov <Alexander.Udalov@jetbrains.com>
Pavel Kunyavskiy