Restricted open: fix shadowing

[W95Psp]

Consider the following three modules:

module A
let a = "A.a"
let b = "A.b"

module B
let a = "B.a"
let b = "B.b"
include A {a}

module C
include B
let _ = b

Running fstar.exe C.fst was producing the error:

* Error 72 at /tmp/C.fst(5,8-5,9):
  - Identifier not found: [b]

This PR fixes that bug, I just forgot to filter names in push_include'.

I also had to add a filter method (and implem) for setlike, does that looks fine @mtzguido?

[mtzguido]

Looks great Lucas, thanks! I added a test for the resolution, merging.

[W95Psp]

Ah, nice, thanks for adding the test!