consider removing `EmptyStatement` node from the AST

[MichaelBuhler]

e.g. We could use Babel Traverse to pre-process the AST prior to code generation. An EmptyStatement visitor could remove such nodes from the AST.

concern: I wonder if for (;;) {} would produce EmptyStatement nodes?

[MichaelBuhler]

the previous concern about for (;;) {} seems to be no problem at all.

as for removing EmptyStatement nodes, I am thinking that there may be a variety of similar optimizations that could be enabled/disabled via a transpiler flag.