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

tests/compiler/dart2js/cps_ir/expected/argument_refinement_28.js

+// Expectation for test: 
+// import 'dart:math';
+// main() {
+//   var x = int.parse('3');
+//   var y = int.parse('1234');
+//   var z = int.parse('1236');
+//   var w = int.parse('2');
+//   print(x is num);
+//   print(sin(x));
+//   print(x is num);
+// 
+//   print(y is num);
+//   print(log(y));
+//   print(y is num);
+// 
+//   print(z is num);
+//   print(w is num);
+//   print(pow(z, w));
+//   print(z is num);
+//   print(w is num);
+// }
+
+function() {
+  var x = P.int_parse("3", null, null), y = P.int_parse("1234", null, null), z = P.int_parse("1236", null, null), w = P.int_parse("2", null, null), v0 = typeof x === "number", v1;
+  P.print(v0);
+  if (!v0)
+    throw H.wrapException(H.argumentErrorValue(x));
+  P.print(Math.sin(x));
+  P.print(true);
+  v0 = typeof y === "number";
+  P.print(v0);
+  if (!v0)
+    throw H.wrapException(H.argumentErrorValue(y));
+  P.print(Math.log(y));
+  P.print(true);
+  v1 = typeof z === "number";
+  P.print(v1);
+  v0 = typeof w === "number";
+  P.print(v0);
+  if (!v1)
+    throw H.wrapException(H.argumentErrorValue(z));
+  if (!v0)
+    throw H.wrapException(H.argumentErrorValue(w));
+  P.print(Math.pow(z, w));
+  P.print(true);
+  P.print(true);
+}