ntdll: Perform the offset checks also for a serial device.

[Dmitry Timoshkov]

Marvin <testbot at winehq.org> wrote:

> === w7pro64 (32 bit comm) ===
> comm.c:863: Test failed: WaitCommEvent failed with a timeout
> comm.c:875: recovering after WAIT_TIMEOUT...
> comm.c:886: Test failed: WaitCommEvent error 0
> comm.c:888: Test failed: WaitCommEvent: expected EV_TXEMPTY, got 0
> comm.c:892: WaitCommEvent for EV_TXEMPTY took 1014 ms (timeout 1000)
> comm.c:894: Test failed: WaitCommEvent used 1014 ms for waiting
> comm.c:1561: test_AbortWaitCts timeout 500 handle 000000F8
> comm.c:1528:  Changing CommMask on the fly for handle 000000F8 after timeout 500

This VM is broken, my working computer runs Windows 7 Pro 64-bit on
real hardware, and I run both 32-bit and 64-bit tests with and without
serial devices powered on.

-- 
Dmitry.