fixes #24402; Memory leak under Arc/Orc on inline iterators with nested seq

[ringabout]

fixes #24402

iterator myPairsInline*[T](twoDarray: seq[seq[T]]): (int, seq[T]) {.inline.} =
  for indexValuePair in twoDarray.pairs:
    yield indexValuePair

proc innerTestTotalMem() =
  var my2dArray: seq[seq[int32]] = @[]

  # fill with some data...
  for i in 0'i32..100:
    var z = @[i, i+1]
    my2dArray.add z

  for oneDindex, innerArray in myPairsInline(my2dArray):
    discard

innerTestTotalMem()

In for oneDindex, innerArray in myPairsInline(my2dArray), oneDindex and innerArray becomes cursors because they satisfy the criterion of isSimpleIteratorVar. On the one hand, it is not correct to have them point to the temporary generated by tuple unpacking, which left the memory of the temporary uncleaned up. On the other hand, we don't need to generate a temporary for a symbol node when unpacking the tuple.

[github-actions]

Thanks for your hard work on this PR!
The lines below are statistics of the Nim compiler built from 21420d8

Hint: mm: orc; opt: speed; options: -d:release
177497 lines; 8.663s; 653.258MiB peakmem