[Enhancement] Set default value of chunk_reserved_bytes_limit to 0 (b…

…ackport #51263) (#51414)

Co-authored-by: trueeyu <lxhhust350@qq.com>

be/src/common/config.h

@@ -473,7 +473,7 @@ CONF_Bool(use_mmap_allocate_chunk, "false");
 // Chunk Allocator's reserved bytes limit,
 // Default value is 2GB, increase this variable can improve performance, but will
 // acquire more free memory which can not be used by other modules
-CONF_Int64(chunk_reserved_bytes_limit, "2147483648");
+CONF_Int64(chunk_reserved_bytes_limit, "0");
 
 // for pprof
 CONF_String(pprof_profile_dir, "${STARROCKS_HOME}/log");