MDL-38352 behat: Updating tests

According to non-escaped double quotes
in TableNodes. Also refactoring previous
test affected by the issue.

admin/tool/behat/tests/behat/nasty_strings.feature

@@ -43,7 +43,7 @@ Feature: Transform steps arguments
     And I follow "Edit profile"
     Then I should not see "NASTYSTRING"
     And the "First name" field should match "va\"lue1" value
-    And the "Description" field should match "va\"lue2" value
+    And the "Description" field should match "va\\"lue2" value
     And the "City/town" field should match "va\"lue3" value
 
   @javascript

blocks/tests/behat/restrict_available_blocks.feature

@@ -4,8 +4,7 @@ Feature: Allowed blocks controls
   As an admin
   I need to restrict some blocks to be used in courses
 
-  @javascript
-  Scenario: Blocks can be added with the default permissions
+  Background:
     Given the following "users" exists:
       | username | firstname | lastname | email |
       | teacher1 | Teacher | 1 | teacher1@asd.com |
@@ -15,7 +14,10 @@ Feature: Allowed blocks controls
     And the following "course enrolments" exists:
       | user | course | role |
       | teacher1 | C1 | editingteacher |
-    And I log in as "teacher1"
+
+  @javascript
+  Scenario: Blocks can be added with the default permissions
+    Given I log in as "teacher1"
     And I follow "Course $NASTYSTRING1"
     And I turn editing mode on
     When I add the "Course completion status" block
@@ -25,16 +27,7 @@ Feature: Allowed blocks controls
 
   @javascript
   Scenario: Blocks can not be added when the admin restricts the permissions
-    Given the following "users" exists:
-      | username | firstname | lastname | email |
-      | teacher1 | Teacher | 1 | teacher1@asd.com |
-    And the following "courses" exists:
-      | fullname | shortname | category |
-      | Course $NASTYSTRING1 | C1 | 0 |
-    And the following "course enrolments" exists:
-      | user | course | role |
-      | teacher1 | C1 | editingteacher |
-    And I log in as "admin"
+    Given I log in as "admin"
     And I set the following system permissions of "Teacher" role:
       | block/activity_modules:addinstance | Prohibit |
     And I am on homepage