message: Fix loop unrolling test cases
  These test cases had to be updated post the switch to exclusive upper bound;
  however, the test cases hadn't originally been written to check correctly; as
  a result, they didn't fail and weren't updated. Update test case and fix
  upper bound.
diff: @@ -433,12 +433,16 @@ mlfunc @loop_nest_single_iteration_after_unroll(%N: index) {
  // UNROLL-BY-4-LABEL: mlfunc @loop_nest_operand1() {
  mlfunc @loop_nest_operand1() {
  // UNROLL-BY-4: for %i0 = 0 to 100 step 2 {
  +// UNROLL-BY-4-NEXT: for %i1 = (d0) -> (0)(%i0) to #map{{[0-9]+}}(%i0) step 4
  +// UNROLL-BY-4-NEXT: %0 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: %1 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: %2 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: %3 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: }
  +// UNROLL-BY-4-NEXT: }
  +// UNROLL-BY-4-NEXT: return
  for %i = 0 to 100 step 2 {
  - // UNROLL-BY-4: %0 = "foo"() : () -> i32
  - // UNROLL-BY-4: %1 = "foo"() : () -> i32
  - // UNROLL-BY-4: %2 = "foo"() : () -> i32
  - // UNROLL-BY-4: %3 = "foo"() : () -> i32
  - for %j = (d0) -> (0) (%i) to (d0) -> (d0 - d0 mod 4 - 1) (%i) {
  + for %j = (d0) -> (0) (%i) to (d0) -> (d0 - d0 mod 4) (%i) {
  %x = "foo"() : () -> i32
  }
  }
  @@ -449,12 +453,16 @@ mlfunc @loop_nest_operand1() {
  // UNROLL-BY-4-LABEL: mlfunc @loop_nest_operand2() {
  mlfunc @loop_nest_operand2() {
  // UNROLL-BY-4: for %i0 = 0 to 100 step 2 {
  +// UNROLL-BY-4-NEXT: for %i1 = (d0) -> (d0)(%i0) to #map{{[0-9]+}}(%i0) step 4 {
  +// UNROLL-BY-4-NEXT: %0 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: %1 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: %2 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: %3 = "foo"() : () -> i32
  +// UNROLL-BY-4-NEXT: }
  +// UNROLL-BY-4-NEXT: }
  +// UNROLL-BY-4-NEXT: return
  for %i = 0 to 100 step 2 {
  - // UNROLL-BY-4: %0 = "foo"() : () -> i32
  - // UNROLL-BY-4: %1 = "foo"() : () -> i32
  - // UNROLL-BY-4: %2 = "foo"() : () -> i32
  - // UNROLL-BY-4: %3 = "foo"() : () -> i32
  - for %j = (d0) -> (d0) (%i) to (d0) -> (5*d0 + 3) (%i) {
  + for %j = (d0) -> (d0) (%i) to (d0) -> (5*d0 + 4) (%i) {
  %x = "foo"() : () -> i32
  }
  }
  