Consistently use the compat wrappers for file IO

As long as WelsFileHandle* is equal to FILE* this doesn't matter,
but for consistency use the WelsF* functions for all handles
opened by WelsFopen, and use WelsFileHandle* as type for it
instead of FILE*.

codec/encoder/core/src/encoder_ext.cpp

@@ -1789,7 +1789,7 @@ void FreeMemorySvc (sWelsEncCtx** ppCtx) {
 
 #ifdef ENABLE_TRACE_FILE
     if (NULL != pCtx->pFileLog) {
-      fclose (pCtx->pFileLog);
+      WelsFclose (pCtx->pFileLog);
       pCtx->pFileLog	= NULL;
     }
     pCtx->uiSizeLog	= 0;