new deconflict strategy for dealing with conflict names

[underfin]

If some symbols conflict, need to assign a new name to avoid name conflict. Here has two strategy to assign new name.

1. the assigned new name is a new name at scope. Esbuild used it.
2. the assigned new name maybe conflict and also rename conflict names.

Think the scope has a/a$1/a$2 symbols declared. The strategy 2 will caused a/a$1/a$2 every symbol need to rename, The strategy 1 will only rename once a -> a$3.

Original discuss is here #365.

[underfin]

1. the assigned new name is a new name at scope. Esbuild used it.

We should use it, because it will reduce soucemap token names size, and it will reduce the overhead of name hash calculate and vlq mapping.

related oxc-project/oxc#2753.

[hyf0]

I understand esbuild could assign new name in one shot. But I'm not sure I understand this. Could you give an example to show why now we will generate more types for names filed of sourcemap.

And for the generated sourcemap, how much we are bigger than esbunild.