psxtests/psxkey08: Do not allocate task IDs

We have a unified work area.  So depending on the memory layout the

    task_id_p = malloc( sizeof( rtems_id ) );
    rtems_test_assert( task_id_p );

or the

    sc = rtems_task_create(
      rtems_build_name('T','A',created_task_count, ' '),
      1,
      RTEMS_MINIMUM_STACK_SIZE,
      RTEMS_DEFAULT_MODES,
      RTEMS_DEFAULT_ATTRIBUTES,
      task_id_p
    );
    rtems_test_assert(
      (sc == RTEMS_UNSATISFIED) ||
      (sc == RTEMS_TOO_MANY) ||
      (sc == RTEMS_SUCCESSFUL)
    );

may fail.  If we are unlucky then we hit the first case and the test
fails.
psxtests/psxkey08: Limit workspace size

This avoids large test execution times on targets with a big RAM.
psxtests/psxkey07: Account for RTEMS_TOO_MANY
psxtests/psxkey07: Limit workspace size

This avoids large test execution times on targets with a big RAM.
psxtests/psxkey07: Do not allocate task IDs