private void replaceNode(EscapeSet newNode, EscapeSet oldNode) {
    for (EscapeSet e : oldNode.parentSets) {
      e.childSets.remove(oldNode);
      e.childSets.add(newNode);
      newNode.parentSets.add(e);
    }
    for (EscapeSet e : oldNode.childSets) {
      e.parentSets.remove(oldNode);
      e.parentSets.add(newNode);
      newNode.childSets.add(e);
    }
  }
Merges all links in the lattice among two EscapeSets. On return, the newNode will have its old
links as well as all links from the oldNode. The oldNode has all its links removed.

@param newNode {@code non-null;} the EscapeSet to merge all links into
@param oldNode {@code non-null;} the EscapeSet to remove all links from
android/android_framework/dex-maker/src/main/java/com/android/dx/ssa/EscapeAnalysis.java