Core: Add memory to the error event to allow late event listeners

Cherry-picked from 15acb36 (3.0.0-dev).
> HTML Reporter: Add support for displaying early errors
> Ref #1786.

Author: Krinkle

src/events.js

@@ -12,6 +12,7 @@ const SUPPORTED_EVENTS = [
   'runEnd'
 ];
 const MEMORY_EVENTS = [
+  'error',
   'runEnd'
 ];
 
@@ -40,7 +41,7 @@ export function emit (eventName, data) {
     callbacks[i](data);
   }
 
-  if (inArray(MEMORY_EVENTS, eventName)) {
+  if (inArray(eventName, MEMORY_EVENTS)) {
     config._event_memory[eventName] = data;
   }
 }

test/cli/fixtures/event-error-memory.js

@@ -0,0 +1,26 @@
+QUnit.on('error', function (error) {
+  console.log(`# early error ${error}`);
+
+  setTimeout(function () {
+    QUnit.on('error', function (error) {
+      console.log(`# late error ${error}`);
+    });
+  });
+});
+
+setTimeout(function () {
+  boom();
+});
+
+QUnit.module('First', function () {
+  QUnit.test('A', function (assert) {
+    assert.true(true);
+  });
+  QUnit.test('B', function (assert) {
+    const done = assert.async();
+    setTimeout(function () {
+      assert.true(true);
+      done();
+    });
+  });
+});

test/cli/fixtures/event-error-memory.tap.txt

@@ -0,0 +1,24 @@
+# command: ["qunit", "event-error-memory.js"]
+
+TAP version 13
+not ok 1 global failure
+  ---
+  message: ReferenceError: boom is not defined
+  severity: failed
+  stack: |
+    ReferenceError: boom is not defined
+        at /qunit/test/cli/fixtures/event-error-memory.js:12:3
+        at internal
+  ...
+Bail out! ReferenceError: boom is not defined
+# early error ReferenceError: boom is not defined
+ok 2 First > A
+# late error ReferenceError: boom is not defined
+ok 3 First > B
+1..3
+# pass 2
+# skip 0
+# todo 0
+# fail 1
+
+# exit code: 1