Don't leak DirectSound thread handles

The previous code refrained from calling CloseHandle on
_beingthreadex()-created threads, citing "documentation". Actually the
official docs suggest the exact opposite:

https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/endthread-endthreadex

> when you use _beginthreadex and _endthreadex, you must close the
> thread handle by calling the Win32 CloseHandle API

This means the previous code would leak the thread handle.

src/hostapi/dsound/pa_win_ds.c

@@ -106,12 +106,10 @@
 
 #if !defined(__CYGWIN__) && !defined(UNDER_CE)
 #define CREATE_THREAD (HANDLE)_beginthreadex
-#undef CLOSE_THREAD_HANDLE /* as per documentation we don't call CloseHandle on a thread created with _beginthreadex */
 #define PA_THREAD_FUNC static unsigned WINAPI
 #define PA_THREAD_ID unsigned
 #else
 #define CREATE_THREAD CreateThread
-#define CLOSE_THREAD_HANDLE CloseHandle
 #define PA_THREAD_FUNC static DWORD WINAPI
 #define PA_THREAD_ID DWORD
 #endif
@@ -3051,9 +3049,7 @@ static PaError StartStream( PaStream *s )
 #ifndef PA_WIN_DS_USE_WMME_TIMER
     if( stream->processingThread )
     {
-#ifdef CLOSE_THREAD_HANDLE
-        CLOSE_THREAD_HANDLE( stream->processingThread ); /* Delete thread. */
-#endif
+        CloseHandle( stream->processingThread ); /* Delete thread. */
         stream->processingThread = NULL;
     }
 #endif
@@ -3092,10 +3088,8 @@ static PaError StopStream( PaStream *s )
         if( WaitForSingleObject( stream->processingThreadCompleted, 30*100 ) == WAIT_TIMEOUT )
             return paUnanticipatedHostError;
 
-#ifdef CLOSE_THREAD_HANDLE
         CloseHandle( stream->processingThread ); /* Delete thread. */
         stream->processingThread = NULL;
-#endif
 
     }
 #endif