pgsql: Rename PGPROC->vacuumFlags to statusFlags

Rename PGPROC->vacuumFlags to statusFlags

With more flags associated to a PGPROC entry that are not related to
vacuum (currently existing or planned), the name "statusFlags" describes
its purpose better.

(The same is done to the mirroring PROC_HDR->vacuumFlags.)

No functional changes in this commit.

This was suggested first by Hari Babu Kommi in [1] and then by Michael
Paquier at [2].

[1] https://postgr.es/m/CAJrrPGcsDC-oy1AhqH0JkXYa0Z2AgbuXzHPpByLoBGMxfOZMEQ@mail.gmail.com
[2] https://postgr.es/m/20200820060929.GB3730@paquier.xyz

Author: Dmitry Dolgov <9erthalion6(at)gmail(dot)com>
Reviewed-by: Álvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
Discussion: https://postgr.es/m/20201116182446.qcg3o6szo2zookyr@localhost

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/cd9c1b3e197a9b53b840dcc87eb41b04d601a5f9

Modified Files
--------------
src/backend/access/transam/twophase.c | 2 +-
src/backend/commands/vacuum.c | 6 ++--
src/backend/postmaster/autovacuum.c | 6 ++--
src/backend/replication/logical/logical.c | 4 +--
src/backend/replication/slot.c | 4 +--
src/backend/storage/ipc/procarray.c | 54 +++++++++++++++----------------
src/backend/storage/lmgr/deadlock.c | 4 +--
src/backend/storage/lmgr/proc.c | 20 ++++++------
src/include/storage/proc.h | 13 ++++----
9 files changed, 57 insertions(+), 56 deletions(-)