pgsql: Generate a few more functions of pgstatfuncs.c with macros

Generate a few more functions of pgstatfuncs.c with macros

Two new macros are added with their respective functions switched to
use them. These are for functions with millisecond stats, with and
without "xact" in their names (for the stats that can be tracked within
a transaction).

While on it, prefix the macro for float8 on database entries with "_MS",
as it does a us->ms conversion, based on a suggestion from Andres
Freund.

Author: Bertrand Drouvot
Discussion: https://postgr.es/m/6e2efb4f-6fd0-807e-f6bf-94207db8183a@gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/4efd0bf7eaebb3e3f5a3a6edd0865f6973e709a6

Modified Files
--------------
src/backend/utils/adt/pgstatfuncs.c | 89 +++++++++++++++++--------------------
1 file changed, 41 insertions(+), 48 deletions(-)