function testSplit_Case2() {
  var tree = insertToTree(19);
  var expected =
      '11[27]\n' +
      '_{2|12}_\n' +
      '2[13|21]  12[31|45]\n' +
      '_{0|1|3}11  2{5|7|9}11\n' +
      '0[3|5|9|11]  1[13|14|15|17]  3[21|22|23|25]' +
      '  5[27|29]  7[31|38]  9[45|47|49]\n' +
      '_{3/5/9/11}2  0{13/14/15/17}2  1{21/22/23/25}2' +
      '  3{27/29}12  5{31/38}12  7{45/47/49}12\n';
  assertEquals(expected, tree.toString());
}
Split of leaf node inducing split of internal nodes and a new level.

                       13|21|27|31
    /          /            |         \         \
3|5|9|11  13|14|15|17  21|22|23|25  27|29  31|38|45|47

insert 49
                             27
                /                            \
             13|21                         31|45
    /          |            \          /     |      \
3|5|9|11  13|14|15|17  21|22|23|25  27|29  31|38  45|47|49