- use ResolvedCall where possible
- 'call' parameter to invokeMethodWithArguments was used only to generate
callee, e.g. in "A()" where A is an expression which can be invoke()'d.
In case of constructors and enum entry delegation specifiers there's no need
to generate callee, so 'call' is made Nullable with a subsequent assert
- remove generateJavaConstructorCall() method, since it did no useful work.
Java constructor invocation is broken anyway and needs to be fixed (KT-3532)
- minor code style / formatting issues fixed, several methods renamed to better
reflect semantics
