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

tests/compiler/dart2js/cps_ir/expected/basic_1.js

+// Expectation for test: 
+// main() {
+//   var e = 1;
+//   var l = [1, 2, 3];
+//   var m = {'s': 1};
+// 
+//   print('(' ')');
+//   print('(${true})');
+//   print('(${1})');
+//   print('(${[1, 2, 3]})');
+//   print('(${{'s': 1}})');
+//   print('($e)');
+//   print('($l)');
+//   print('($m)');
+// }
+
+function() {
+  var l = [1, 2, 3], m = P.LinkedHashMap_LinkedHashMap$_literal(["s", 1]);
+  P.print("()");
+  P.print("(true)");
+  P.print("(1)");
+  P.print("(" + P.IterableBase_iterableToFullString([1, 2, 3], "[", "]") + ")");
+  P.print("(" + P.Maps_mapToString(P.LinkedHashMap_LinkedHashMap$_literal(["s", 1])) + ")");
+  P.print("(1)");
+  P.print("(" + P.IterableBase_iterableToFullString(l, "[", "]") + ")");
+  P.print("(" + P.Maps_mapToString(m) + ")");
+}