Make this names context-dependent

[jvican]

It occurred to me that because of the name heuristics, this can be a common source of conservative recompilation when changes in the source code happens. We fixed a similar issue with constructors in #288, and the same rationale applies here. I'm optimistic that, just like that change, this improvement can reduce unnecessary compilations and increase the efficiency of the recompilations.

[jvican]

Another common name is package, which we may just want to outright remove.

[jvican]

Like this, synthesized defs like the ones generated by default arguments (and maybe delayed init?) should also be prepended with the class name they are owned by to minimize recompilations. Currently: <init>$default$1, should be: foo;MyBar;<init>$default$1 just as in the PR in
#288 (/cc @smarter)