Check in codegen test expectations.

test/codegen/expect/language/stacktrace_test.js

Index: test/codegen/expect/language/stacktrace_test.js
diff --git a/test/codegen/expect/language/stacktrace_test.js b/test/codegen/expect/language/stacktrace_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..e5e5846716ba92b795f902260a4b639a093a14ce
--- /dev/null
+++ b/test/codegen/expect/language/stacktrace_test.js
@@ -0,0 +1,29 @@
+dart_library.library('language/stacktrace_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__stacktrace_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const stacktrace_test = Object.create(null);
+  let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [])))();
+  stacktrace_test.main = function() {
+    let ex = core.Exception.new("fail");
+    try {
+      dart.throw(ex);
+    } catch (e) {
+      if (core.Exception.is(e)) {
+        let st = dart.stackTrace(e);
+        expect$.Expect.equals(ex, e);
+        expect$.Expect.isTrue(st.toString()[dartx.endsWith]("\n"));
+      } else
+        throw e;
+    }
+
+  };
+  dart.fn(stacktrace_test.main, VoidTovoid());
+  // Exports:
+  exports.stacktrace_test = stacktrace_test;
+});