MDL-58265 core_test: replace I turn editing on steps

Also remove few more unnecessary steps that redirects behat to
site home page to actually get to the course.

Part of MDL-55611 epic.

admin/tool/recyclebin/tests/behat/basic_functionality.feature

@@ -25,8 +25,7 @@ Feature: Basic recycle bin functionality
 
   Scenario: Restore a deleted assignment
     Given I log in as "teacher1"
-    And I am on course page "Course 1"
-    And I turn editing mode on
+    And I am on "Course 1" course homepage with editing mode on
     And I add a "Assignment" to section "1" and I fill the form with:
       | Assignment name | Test assign |
       | Description | Test |
@@ -37,8 +36,7 @@ Feature: Basic recycle bin functionality
     And I click on "Restore" "link" in the "region-main" "region"
     And I should see "'Test assign' has been restored"
     And I wait to be redirected
-    And I am on homepage
-    And I am on course page "Course 1"
+    And I am on "Course 1" course homepage
     And I should see "Test assign" in the "Topic 1" "section"
 
   Scenario: Restore a deleted course
@@ -64,8 +62,7 @@ Feature: Basic recycle bin functionality
   @javascript
   Scenario: Deleting a single item from the recycle bin
     Given I log in as "teacher1"
-    And I am on course page "Course 1"
-    And I turn editing mode on
+    And I am on "Course 1" course homepage with editing mode on
     And I add a "Assignment" to section "1" and I fill the form with:
       | Assignment name | Test assign |
       | Description | Test |
@@ -84,8 +81,7 @@ Feature: Basic recycle bin functionality
   @javascript
   Scenario: Deleting all the items from the recycle bin
     Given I log in as "teacher1"
-    And I am on course page "Course 1"
-    And I turn editing mode on
+    And I am on "Course 1" course homepage with editing mode on
     And I add a "Assignment" to section "1" and I fill the form with:
       | Assignment name | Test assign 1 |
       | Description | Test 1 |