Reduce bit tables to 8bit

This saves some 1.7Kb in rodata section (x86_64, zstd tool),
while assembler code stays the same except
the type of a few load/extend instructions.

Should not have negative performance implications.

lib/compress/zstd_compress.c

@@ -3263,7 +3263,7 @@ static size_t ZSTD_estimateBlockSize_literal(const BYTE* literals, size_t litSiz
 static size_t ZSTD_estimateBlockSize_symbolType(symbolEncodingType_e type,
                         const BYTE* codeTable, size_t nbSeq, unsigned maxCode,
                         const FSE_CTable* fseCTable,
-                        const U32* additionalBits,
+                        const U8* additionalBits,
                         short const* defaultNorm, U32 defaultNormLog, U32 defaultMax,
                         void* workspace, size_t wkspSize)
 {

lib/compress/zstd_compress_superblock.c

@@ -325,7 +325,7 @@ static size_t ZSTD_estimateSubBlockSize_literal(const BYTE* literals, size_t lit
 static size_t ZSTD_estimateSubBlockSize_symbolType(symbolEncodingType_e type,
                         const BYTE* codeTable, unsigned maxCode,
                         size_t nbSeq, const FSE_CTable* fseCTable,
-                        const U32* additionalBits,
+                        const U8* additionalBits,
                         short const* defaultNorm, U32 defaultNormLog, U32 defaultMax,
                         void* workspace, size_t wkspSize)
 {