inline iterator called twice gives cgen error

[timotheecour]

reduced from #18535 (comment) /cc @brightly-salty

Example

# iterator envPairs*(): int {.closure.} = # Error: internal error: environment misses: foo
iterator envPairs*(): int =
  var foo: seq[int]
  proc fun() =
    foo = @[]
  fun()
  yield 3

proc main() =
  for a in envPairs():
    discard
  for a in envPairs():
    discard
static: main() # nim c in vm: ok
# static: main() # nim js in vm: Error: cannot evaluate at compile time: foo
main() # nim c: @mt12609.nim.c:372:5: error: use of undeclared identifier 'colonenv_'; did you mean 'colonenv__2'?
# main() # nim js: # Error: internal error: symbol has no generated name: foo

Current Output

/@mt12609.nim.c:372:5: error: use of undeclared identifier 'colonenv_'; did you mean 'colonenv__2'?
                (*colonenv_).foo1 = (tySequence__qwqHTkRvwhrRyENtudHQ7g*)0;
                  ^~~~~~~~~
                  colonenv__2
/Users/timothee/git_clone/nim/timn/build/nimcache/@mt12609.nim.c:364:65: note: 'colonenv__2' declared here
                tyObject_Env_t12609dotnim_envPairs___Dwg4Sd9awieN34NfR6DSgaw* colonenv__2;
                                                                              ^
/Users/timothee/git_clone/nim/timn/build/nimcache/@mt12609.nim.c:375:46: error: use of undeclared identifier 'colonenv_'; did you mean 'colonenv__2'?
                T4_.ClP_0 = fun_t4950544857_3; T4_.ClE_0 = colonenv_;

Expected Output

works

Additional Information

1.5.1 73ce40a

[timotheecour]

closing as duplicate of #14165