Add stack traces on async failures (#6008)

* add stacktraces to async matchers

* add stack trace on spec timeout

* link to PR

* remove uninteresting frame from snapshot

* Add stack trace for thrown non-`Error`s

* more node 6 stack cleanup

* please flow gods

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 ### Features
 
+* `[expect]` Add stack trace for async errors
+  ([#6008](https://github.com/facebook/jest/pull/6008))
+* `[jest-jasmine2]` Add stack trace for timeouts
+  ([#6008](https://github.com/facebook/jest/pull/6008))
+* `[jest-jasmine2]` Add stack trace for thrown non-`Error`s
+  ([#6008](https://github.com/facebook/jest/pull/6008))
 * `[jest-runtime]` Prevent modules from marking themselves as their own parent
   ([#5235](https://github.com/facebook/jest/issues/5235))
 * `[jest-mock]` Add support for auto-mocking generator functions

integration-tests/__tests__/__snapshots__/expect-async-matcher.test.js.snap

@@ -1,8 +1,7 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`shows the correct errors in stderr when failing tests 1`] = `
-Object {
-  "rest": "FAIL __tests__/failure.test.js
+"FAIL __tests__/failure.test.js
   ✕ fail with expected non promise values
   ✕ fail with expected non promise values and not
   ✕ fail with expected promise values
@@ -30,30 +29,47 @@ Object {
 
   ● fail with expected promise values
 
-    Error
-      Error: Expected value to have length:
-        2
-      Received:
-        1
-      received.length:
-        1
+    Expected value to have length:
+      2
+    Received:
+      1
+    received.length:
+      1
+
+      22 | 
+      23 | it('fail with expected promise values', async () => {
+    > 24 |   await (expect(Promise.resolve([1])): any).resolves.toHaveLengthAsync(
+         |                                                      ^
+      25 |     Promise.resolve(2)
+      26 |   );
+      27 | });
+      
+      at __tests__/failure.test.js:24:54
+      at __tests__/failure.test.js:11:191
+      at __tests__/failure.test.js:11:437
+      at __tests__/failure.test.js:11:99
 
   ● fail with expected promise values and not
 
-    Error
-      Error: Expected value to not have length:
-        2
-      Received:
-        1,2
-      received.length:
-        2
+    Expected value to not have length:
+      2
+    Received:
+      1,2
+    received.length:
+      2
+
+      28 | 
+      29 | it('fail with expected promise values and not', async () => {
+    > 30 |   await (expect(Promise.resolve([1, 2])).resolves.not: any).toHaveLengthAsync(
+         |                                                             ^
+      31 |     Promise.resolve(2)
+      32 |   );
+      33 | });
+      
+      at __tests__/failure.test.js:30:61
+      at __tests__/failure.test.js:11:191
+      at __tests__/failure.test.js:11:437
+      at __tests__/failure.test.js:11:99
 
-",
-  "summary": "Test Suites: 1 failed, 1 total
-Tests:       4 failed, 4 total
-Snapshots:   0 total
-Time:        <<REPLACED>>
-Ran all test suites matching /failure.test.js/i.
-",
-}
+"
 `;