Handle unfinished promise-awaiting tests

lib/test.js

@@ -260,6 +260,7 @@ Test.prototype.endAll = function () {
     child._bailedOut = true
   }
 
+  this._mustDeferEnd = false
   this.end(IMPLICIT)
 }
 

test/test/unfinished-promise-bail.tap

@@ -0,0 +1,13 @@
+TAP version 13
+# Subtest: parent
+    # Subtest: child
+        # Subtest: grandchild
+            1..2
+            ok 1 - ok
+            not ok 2 - test unfinished: grandchild
+              ---
+              {"at":{"column":14,"file":"test/test/unfinished-promise.js","line":4},"count":1,"plan":2,"source":"return t.test('grandchild', function (t) {\n"}
+              ...
+            Bail out! # test unfinished: grandchild
+Bail out! # test unfinished: grandchild
+

test/test/unfinished-promise.js

@@ -0,0 +1,9 @@
+var t = require('../..')
+t.test('parent', function (t) {
+  return t.test('child', function (t) {
+    return t.test('grandchild', function (t) {
+      t.plan(2)
+      t.pass('ok')
+    })
+  })
+})

test/test/unfinished-promise.tap

@@ -0,0 +1,34 @@
+TAP version 13
+# Subtest: parent
+    # Subtest: child
+        # Subtest: grandchild
+            1..2
+            ok 1 - ok
+            not ok 2 - test unfinished: grandchild
+              ---
+              {"at":{"column":14,"file":"test/test/unfinished-promise.js","line":4},"count":1,"plan":2,"source":"return t.test('grandchild', function (t) {\n"}
+              ...
+            # failed 1 of 2 tests
+        not ok 1 - grandchild ___/# time=[0-9.]+(ms)?/~~~
+          ---
+          {"at":{"column":14,"file":"test/test/unfinished-promise.js","line":4},"results":{"count":2,"fail":1,"ok":false,"pass":1,"plan":{"end":2,"start":1}},"source":"return t.test('grandchild', function (t) {\n"}
+          ...
+
+        1..1
+        # failed 1 of 1 tests
+    not ok 1 - child ___/# time=[0-9.]+(ms)?/~~~
+      ---
+      {"at":{"column":12,"file":"test/test/unfinished-promise.js","line":3},"results":{"count":1,"fail":1,"ok":false,"pass":0,"plan":{"end":1,"start":1}},"source":"return t.test('child', function (t) {\n"}
+      ...
+
+    1..1
+    # failed 1 of 1 tests
+not ok 1 - parent ___/# time=[0-9.]+(ms)?/~~~
+  ---
+  {"at":{"column":3,"file":"test/test/unfinished-promise.js","line":2},"results":{"count":1,"fail":1,"ok":false,"pass":0,"plan":{"end":1,"start":1}},"source":"t.test('parent', function (t) {\n"}
+  ...
+
+1..1
+# failed 1 of 1 tests
+___/# time=[0-9.]+(ms)?/~~~
+