Summary:
WriteBuffer move ctor does not initialize consumption_.
So segmentation fault could happen when WriteBuffer is constucted over non zeroed memory.
Jira: DB-12860

Original commit: 885b72b0cb32219263519b59b56eca9b5512539b/D38158

Test Plan: WriteBufferTest.MoveCtor

Reviewers: rthallam, esheng

Reviewed By: rthallam

Subscribers: ybase

Differential Revision: https://phorge.dev.yugabyte.com/D38302