ControlFlow immutableCopy() {
    return new ImmutableControlFlow(myInstructions.toArray(new Instruction[0]),
                                    new Object2LongOpenHashMap<>(myElementToOffsetMap),
                                    myElementsForInstructions.toArray(PsiElement.EMPTY_ARRAY),
                                    myConstantConditionOccurred);
  }
ControlFlow immutableCopy()