cpsir unittests: move all unittests into individual files and test runners.

tests/compiler/dart2js/cps_ir/expected/gvn_1.js

+// Expectation for test: 
+// foo(x, list) {
+//   var sum = 0;
+//   for (int k = 0; k < 10; k++) {
+//     // Everything can be hoisted out up to the index access which is
+//     // blocked by the bounds check.
+//     var a = x.left.left;
+//     var b = x.left.right;
+//     var c = x.right.left;
+//     var d = x.right.right;
+//     var i = a.value + c.value;
+//     var j = b.value + d.value;
+//     var z = list[i * j] + i;
+//     sum += z;
+//   }
+//   return sum;
+// }
+// // Use a different class for each level in the tree, so type inference
+// // is not confused.
+// class Root {
+//   Branch left, right;
+//   Root(this.left, this.right);
+// }
+// class Branch {
+//   Leaf left, right;
+//   Branch(this.left, this.right);
+// }
+// class Leaf {
+//   int value;
+//   Leaf(this.value);
+// }
+// main() {
+//   var x1 = new Leaf(1);
+//   var x2 = new Leaf(10);
+//   var x3 = new Leaf(20);
+//   var x4 = new Leaf(-10);
+//   var y1 = new Branch(x1, x2);
+//   var y2 = new Branch(x3, x4);
+//   var z  = new Root(y1, y2);
+//   print(foo(z, [1,2,3,4,5,6,7,8,9,10]));
+// }
+
+function() {
+  var v0 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], i = 1 + 20, v1 = i * (10 + -10), sum = 0, k = 0, line;
+  for (; k < 10; sum += i + v0[v1], ++k)
+    if (v1 < 0 || v1 >= 10)
+      return H.ioore(v0, v1);
+  line = sum === 0 ? 1 / sum < 0 ? "-0.0" : "" + sum : "" + sum;
+  if (typeof dartPrint == "function")
+    dartPrint(line);
+  else if (typeof console == "object" && typeof console.log != "undefined")
+    console.log(line);
+  else if (!(typeof window == "object")) {
+    if (!(typeof print == "function"))
+      throw "Unable to print message: " + String(line);
+    print(line);
+  }
+}