BUG #14838: clock_timestamp() returns same values for each row

The following bug has been logged on the website:

Bug reference: 14838
Logged by: zam zam
Email address: zam6ak(at)gmail(dot)com
PostgreSQL version: 10rc1
Operating system: Windows 10
Description:

Hello

We use clock_timestamp() function in our code and I have noticed that in PG
10 RC1 it returns same values across rows...

Here is the output from 9.6 compare to 10rc1

select version();
-- "PostgreSQL 9.6.3, compiled by Visual C++ build 1800, 64-bit"

select clock_timestamp() from generate_series(1,10)
-- "clock_timestamp"
-- "2017-09-29 09:39:34.820954-04"
-- "2017-09-29 09:39:34.820977-04"
-- "2017-09-29 09:39:34.820979-04"
-- "2017-09-29 09:39:34.820981-04"
-- "2017-09-29 09:39:34.820982-04"
-- "2017-09-29 09:39:34.820983-04"
-- "2017-09-29 09:39:34.820984-04"
-- "2017-09-29 09:39:34.820986-04"
-- "2017-09-29 09:39:34.820987-04"
-- "2017-09-29 09:39:34.820988-04"

select version();
-- "PostgreSQL 10rc1 on x86_64-pc-mingw64, compiled by gcc.exe (Rev5, Built
by MSYS2 project) 4.9.2, 64-bit"

select clock_timestamp() from generate_series(1,10)
-- "clock_timestamp"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"
-- "2017-09-29 09:38:45.779869-04"