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 gives us more precise type information and can enable backend
optimizations. This was motivated by when expressions not compiled
to table switches in the JVM_IR backend.
Fixed KT-36845.
Dmitriy Dolovov