Merge changes I41f027a7,I98d7721f,I855a9bab,I8a3c47dd

* changes:
  gatt_attr: Read GATT Server supported features in a sequence
  eatt: Establish EATT after encryption is done.
  eatt: Use pts mode to pass some L2CAP test cases
  gatt: Add upper tester for Multiple Variable Len notification