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.
Generating IR declarations for use-site substitution overrides leads
to IR that is different from K1 as well as problems in signature
generation which relies on mangling. Use-site substitutions can contain
references to type parameters from the call-site which aren't handled
in mangling.
#KT-57022 Fixed
Dmitriy Dolovov