$460e17ea for-in-register-lifetime.js:1:1
  Registers: 14
  Blocks:    6
  Constants:
    [0] = String("")
    [1] = Int32(1)
    [2] = Int32(2)
    [3] = Int32(3)
    [4] = Undefined

block0:
  [   0] SetGlobal `result`, src:String("")
  [  10] NewObject dst:reg5
  [  20] InitObjectLiteralProperty object:reg5, `a`, src:Int32(1), shape_cache_index:0, property_slot:0
  [  38] InitObjectLiteralProperty object:reg5, `b`, src:Int32(2), shape_cache_index:0, property_slot:1
  [  50] InitObjectLiteralProperty object:reg5, `c`, src:Int32(3), shape_cache_index:0, property_slot:2
  [  68] CacheObjectShape object:reg5
  [  78] SetGlobal `obj`, src:reg5
  [  88] GetGlobal dst:reg5, `obj`
  [  98] JumpNullish condition:reg5, true_target:block3, false_target:block4

block1:
  [  a8] End value:reg5

block2:
  [  b0] ObjectPropertyIteratorNext dst_value:reg7, dst_done:reg8, iterator_object:reg6
  [  c0] JumpIf condition:reg8, true_target:block1, false_target:block5

block3:
  [  d0] End value:reg5

block4:
  [  d8] GetObjectPropertyIterator dst_iterator:reg6, object:reg5
  [  e8] Mov dst:reg5, src:Undefined
  [  f8] Jump target:block2

block5:
  [ 100] SetGlobal `k`, src:reg7
  [ 110] GetGlobal dst:reg9, `result`
  [ 120] GetGlobal dst:reg10, `k`
  [ 130] GetGlobal dst:reg11, `obj`
  [ 140] GetGlobal dst:reg12, `k`
  [ 150] GetByValue dst:reg13, base:reg11, property:reg12 (obj[reg12])
  [ 168] Add dst:reg11, lhs:reg10, rhs:reg13
  [ 178] Add dst:reg10, lhs:reg9, rhs:reg11
  [ 188] SetGlobal `result`, src:reg10
  [ 198] Mov dst:reg5, src:reg10
  [ 1a8] Jump target:block2