Remove INTERNAL type from FailStatus enum

Remove INTERNAL type from FailStatus enum

INTERNAL fail status is treated as FAILED fail status. It is collected
in case of:
* DPL::Exception - should not be thrown by test cased body, as it is used
  in test framework only
* std::exception - which implies that test case is not constructed well
  or there is not enough resources, which may be also passed as Failed
  state in RUNNER_* macros.
* other exceptions - same as std::exception

Change-Id: I8776622afcb9d01739f8780183ad4c5f364deb25