message: Sort in BranchPrefixHoisting
  Summary: Follow-up to {D27929494 (https://github.com/facebook/redex/commit/2505bdfa261db05454f3d1d3b5b53cc427b037ec)}. Keep the hoisting of source-blocks in a deterministic order.
diff: @@ -345,6 +345,12 @@ size_t hoist_insns_for_block(cfg::Block* block,
  std::transform(succ_blocks_set.begin(), succ_blocks_set.end(),
  std::back_inserter(ret),
  [](auto* b) { return std::make_pair(b, b->begin()); });
  +
  + // Need to order in some way for stable insertion of source blocks.
  + std::sort(ret.begin(), ret.end(), [](const auto& lhs, const auto& rhs) {
  + return lhs.first->id() < rhs.first->id();
  + });
  +
  return ret;
  }();
  