core-local array type conversions

Summary:
try to clean up the type conversions and hope it passes on windows.

one interesting thing I learned is that bitshift operations are special: in `x << y`, the result type depends only on the type of `x`, unlike most arithmetic operations where the result type depends on both operands' types.
Closes https://github.com/facebook/rocksdb/pull/2277

Differential Revision: D5050145

Pulled By: ajkr

fbshipit-source-id: f3309e77526ac9612c632bf93a62d99757af9a29
(cherry picked from commit bbe9ee7dd4a542b191ace521ca13b4bdb063008b)

Gbp-Pq: Name 0002-core-local-array-type-conversions.patch

CoreLocalArray class

Summary:
Moved the logic for core-local array out of ConcurrentArena and into a separate class because I want to reuse it for core-local stats.
Closes https://github.com/facebook/rocksdb/pull/2256

Differential Revision: D5011518

Pulled By: ajkr

fbshipit-source-id: a75a7b8f7b7a42fd6273489ada405f14c6be196a
(cherry picked from commit cda5fde2d96624df38afc7f02b6b3e699648c62d)

Gbp-Pq: Name 0001-CoreLocalArray-class.patch

rocksdb-fallthrough-i386

Gbp-Pq: Name rocksdb-fallthrough-i386.patch

libatomic

Gbp-Pq: Name libatomic.patch

virtualenv-never-download

Gbp-Pq: Name virtualenv-never-download.patch

remove ceph.com ref to favicon

Origin: backport, https://github.com/ceph/ceph/commit/409b8923a24ff557c53260842aaff6400054bc9b

Gbp-Pq: Name 0013-remove-ceph.com-ref-to-favicon.patch

fix various spelling errors

Forwarded: https://github.com/ceph/ceph/pull/20831

Gbp-Pq: Name 0010-fix-various-spelling-errors.patch

ceph (12.2.11+dfsg1-2) unstable; urgency=medium

  * [27a321] Fix builds on 32bit architectures
  * [346bfa] Fix linking radosgw without BEAST frontend

[dgit import unpatched ceph 12.2.11+dfsg1-2]

Import ceph_12.2.11+dfsg1-2.debian.tar.xz

[dgit import tarball ceph 12.2.11+dfsg1-2 ceph_12.2.11+dfsg1-2.debian.tar.xz]

Import ceph_12.2.11+dfsg1.orig.tar.xz

[dgit import orig ceph_12.2.11+dfsg1.orig.tar.xz]