MDL-56913 quiz: teachers should see a review link for a preview

So what they see is like what students see.

mod/quiz/tests/behat/preview.feature

@@ -0,0 +1,45 @@
+@mod @mod_quiz
+Feature: Preview a quiz as a teacher
+  In order to verify my quizzes are ready for my students
+  As a teacher
+  I need to be able to preview them
+
+  Background:
+    Given the following "users" exist:
+      | username | firstname | lastname | email               |
+      | teacher  | Teacher   | One      | teacher@example.com |
+    And the following "courses" exist:
+      | fullname | shortname | category |
+      | Course 1 | C1        | 0        |
+    And the following "course enrolments" exist:
+      | user     | course | role    |
+      | teacher  | C1     | teacher |
+    And the following "question categories" exist:
+      | contextlevel | reference | name           |
+      | Course       | C1        | Test questions |
+    And the following "activities" exist:
+      | activity   | name   | intro              | course | idnumber |
+      | quiz       | Quiz 1 | Quiz 1 description | C1     | quiz1    |
+    And the following "questions" exist:
+      | questioncategory | qtype       | name  | questiontext    |
+      | Test questions   | truefalse   | TF1   | First question  |
+      | Test questions   | truefalse   | TF2   | Second question |
+    And quiz "Quiz 1" contains the following questions:
+      | question | page | maxmark |
+      | TF1      | 1    |         |
+      | TF2      | 1    | 3.0     |
+    And I log in as "teacher"
+    And I follow "Course 1"
+
+  @javascript
+  Scenario: Preview a quiz
+    When I follow "Quiz 1"
+    And I press "Preview quiz now"
+    And I click on "True" "radio" in the "First question" "question"
+    And I click on "False" "radio" in the "Second question" "question"
+    And I press "Finish attempt ..."
+    And I press "Submit all and finish"
+    And I click on "Submit all and finish" "button" in the "Confirmation" "dialogue"
+    Then I should see "25.00 out of 100.00"
+    And I follow "Finish review"
+    And "Review" "link" in the "Preview" "table_row" should be visible

mod/quiz/view.php

@@ -78,7 +78,7 @@
 // Create view object which collects all the information the renderer will need.
 $viewobj = new mod_quiz_view_object();
 $viewobj->accessmanager = $accessmanager;
-$viewobj->canreviewmine = $canreviewmine;
+$viewobj->canreviewmine = $canreviewmine || $canpreview;
 
 // Get this user's attempts.
 $attempts = quiz_get_user_attempts($quiz->id, $USER->id, 'finished', true);