dictionary compression use correct file size estimation

when determining compression parameters
to compress one file only.

For multiple files, it still "bets" that files are going to be small.

There was also a bug recently added in ZSTD_CCtx_loadDictionary_advanced()
making it incapable to use pledgedSrcSize to determine compression parameters.

lib/compress/zstd_compress.c

@@ -531,7 +531,7 @@ size_t ZSTD_CCtx_loadDictionary_advanced(
         cctx->cdict = NULL;
     } else {
         ZSTD_compressionParameters const cParams =
-                ZSTD_getCParamsFromCCtxParams(cctx->requestedParams, 0, dictSize);
+                ZSTD_getCParamsFromCCtxParams(cctx->requestedParams, cctx->pledgedSrcSizePlusOne-1, dictSize);
         cctx->cdictLocal = ZSTD_createCDict_advanced(
                                 dict, dictSize,
                                 dictLoadMethod, dictMode,