Substitution of type arguments to non-reified type parameters may lead
to accidental reification, which should not be done (see ^KT-60174 for
examples). So, we should erase them, except the few cases.
^KT-60174: Fixed
^KT-60175: Fixed
The patch adopts and reuses the optimizations from the legacy backend.
The optimizations remove useless temporary variables,
statements and simplify generated JS code.
The optimizations can be disabled by `-Xoptimize-generated-js=false`.
Related to KT-51139
Namely:
- Generate debug info for closing braces, which allows the breakpoints
set on closing braces to be hit
- Generate debug info for 'if' and 'try/catch' statements.
KT-46276