swap has double evaluation bug in vm and js

[timotheecour]

Example

when true:
  proc identity[T](a: var T): var T =
    echo (a, )
    a
  proc main() =
    var a = 1
    var b = 2
    swap(identity(a), identity(b))
  static: main()
  main()

Current Output

nim r main
vm:
(1,)
(1,)
(2,)
(2,)

rt:
(1,)
(2,)

nim r -b:js main
vm:
(1,)
(1,)
(2,)
(2,)

rt:
(1,)
(1,)
(2,)
(2,)

Expected Output

vm:
(1,)
(2,)

rt:
(1,)
(2,)

Additional Information

1.5.1 2b5841c
after #16778:
nim r -b:js main
vm:
(1,)
(1,)
(2,)
(2,)

rt:
(1,)
(1,)

so js+vm and c+vm are still broken after that PR

note that attempts to fix this in VM via addr runs into #16780