[COMMITTERS] pgsql: Consistently declare timestamp variables as TimestampTz.

Consistently declare timestamp variables as TimestampTz.

Twiddle the replication-related code so that its timestamp variables
are declared TimestampTz, rather than the uninformative "int64" that
was previously used for meant-to-be-always-integer timestamps.
This resolves the int64-vs-TimestampTz declaration inconsistencies
introduced by commit 7c030783a, though in the opposite direction to
what was originally suggested.

This required including datatype/timestamp.h in a couple more places
than before.  I decided it would be a good idea to slim down that
header by not having it pull in <float.h> etc, as those headers are
no longer at all relevant to its purpose.  Unsurprisingly, a small number
of .c files turn out to have been depending on those inclusions, so add
them back in the .c files as needed.

Discussion: https://postgr.es/m/26788.1487455319@sss.pgh.pa.us
Discussion: https://postgr.es/m/27694.1487456324@sss.pgh.pa.us

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/c29aff959dc64f7321062e7f33d8c6ec23db53d3

Modified Files
--------------
contrib/auth_delay/auth_delay.c           |  2 ++
contrib/btree_gist/btree_ts.c             |  2 ++
src/backend/access/common/reloptions.c    |  2 ++
src/backend/access/transam/xlog.c         |  1 +
src/backend/commands/prepare.c            |  2 ++
src/backend/executor/nodeBitmapHeapscan.c |  2 ++
src/backend/replication/basebackup.c      | 12 ++++-----
src/backend/replication/logical/worker.c  | 14 +++++-----
src/backend/replication/walreceiver.c     | 10 +++----
src/backend/replication/walsender.c       |  9 ++++---
src/backend/tcop/pquery.c                 |  2 ++
src/backend/utils/adt/nabstime.c          |  1 +
src/backend/utils/cache/inval.c           |  2 ++
src/backend/utils/time/snapmgr.c          | 45 ++++++++++++++++---------------
src/bin/pg_basebackup/pg_recvlogical.c    | 18 ++++++-------
src/bin/pg_basebackup/receivelog.c        | 22 +++++++--------
src/bin/pg_basebackup/streamutil.c        | 20 +++++++-------
src/bin/pg_basebackup/streamutil.h        |  7 ++---
src/include/datatype/timestamp.h          |  4 ---
src/include/utils/snapmgr.h               |  7 ++---
src/include/utils/snapshot.h              |  3 ++-
src/include/utils/timestamp.h             |  7 -----
22 files changed, 100 insertions(+), 94 deletions(-)