Use fixed dates in test for consistent results.

Taken from upstream:

  https://github.com/timescale/timescaledb/commit/1d0670e703862b284c241ab797404f851b25b5df

diff --git a/test/expected/copy-12.out b/test/expected/copy-12.out
index 5cb28a45a2..37abf6f6ff 100644
--- a/test/expected/copy-12.out
+++ b/test/expected/copy-12.out
@@ -324,13 +324,12 @@ INSERT INTO hyper_copy_large
 SELECT time,
 random() AS value
 FROM
-generate_series(now() - INTERVAL '1 months', now() - INTERVAL '1 day',
-  INTERVAL '1 hour') AS g1(time)
+generate_series('2022-01-01', '2022-01-31', INTERVAL '1 hour') AS g1(time)
 ORDER BY time;
 SELECT COUNT(*) FROM hyper_copy_large;
  count 
 -------
-   697
+   721
 (1 row)
 
 -- Migrate data to chunks by using copy
@@ -345,7 +344,7 @@ NOTICE:  migrating data to chunks
 SELECT COUNT(*) FROM hyper_copy_large;
  count 
 -------
-   697
+   721
 (1 row)
 
 ----------------------------------------------------------------
diff --git a/test/expected/copy-13.out b/test/expected/copy-13.out
index 02bf913eff..89e16fe8e2 100644
--- a/test/expected/copy-13.out
+++ b/test/expected/copy-13.out
@@ -324,13 +324,12 @@ INSERT INTO hyper_copy_large
 SELECT time,
 random() AS value
 FROM
-generate_series(now() - INTERVAL '1 months', now() - INTERVAL '1 day',
-  INTERVAL '1 hour') AS g1(time)
+generate_series('2022-01-01', '2022-01-31', INTERVAL '1 hour') AS g1(time)
 ORDER BY time;
 SELECT COUNT(*) FROM hyper_copy_large;
  count 
 -------
-   697
+   721
 (1 row)
 
 -- Migrate data to chunks by using copy
@@ -345,7 +344,7 @@ NOTICE:  migrating data to chunks
 SELECT COUNT(*) FROM hyper_copy_large;
  count 
 -------
-   697
+   721
 (1 row)
 
 ----------------------------------------------------------------
diff --git a/test/expected/copy-14.out b/test/expected/copy-14.out
index 02bf913eff..89e16fe8e2 100644
--- a/test/expected/copy-14.out
+++ b/test/expected/copy-14.out
@@ -324,13 +324,12 @@ INSERT INTO hyper_copy_large
 SELECT time,
 random() AS value
 FROM
-generate_series(now() - INTERVAL '1 months', now() - INTERVAL '1 day',
-  INTERVAL '1 hour') AS g1(time)
+generate_series('2022-01-01', '2022-01-31', INTERVAL '1 hour') AS g1(time)
 ORDER BY time;
 SELECT COUNT(*) FROM hyper_copy_large;
  count 
 -------
-   697
+   721
 (1 row)
 
 -- Migrate data to chunks by using copy
@@ -345,7 +344,7 @@ NOTICE:  migrating data to chunks
 SELECT COUNT(*) FROM hyper_copy_large;
  count 
 -------
-   697
+   721
 (1 row)
 
 ----------------------------------------------------------------
diff --git a/test/sql/copy.sql.in b/test/sql/copy.sql.in
index 91402c2ab8..bba4265064 100644
--- a/test/sql/copy.sql.in
+++ b/test/sql/copy.sql.in
@@ -276,8 +276,7 @@ INSERT INTO hyper_copy_large
 SELECT time,
 random() AS value
 FROM
-generate_series(now() - INTERVAL '1 months', now() - INTERVAL '1 day',
-  INTERVAL '1 hour') AS g1(time)
+generate_series('2022-01-01', '2022-01-31', INTERVAL '1 hour') AS g1(time)
 ORDER BY time;
 
 SELECT COUNT(*) FROM hyper_copy_large;
 (<user-account>)[home-directory]: Mark as
thunked and add a default value.
(default-home-directory): New procedure.
* doc/guix.texi (User Accounts): Remove 'home-directory' from example.
* gnu/system/examples/bare-bones.tmpl: Likewise.
* gnu/system/examples/beaglebone-black.tmpl: Likewise.
* gnu/system/examples/desktop.tmpl: Likewise.
* gnu/system/examples/docker-image.tmpl: Likewise.
* gnu/system/examples/lightweight-desktop.tmpl: Likewise.
* gnu/system/install.scm (installation-os): Likewise.
* gnu/tests.scm (%simple-os): Likewise.
* gnu/tests/install.scm (%minimal-os, %minimal-os-on-vda):
(%separate-home-os, %encrypted-root-os, %btrfs-root-os): Likewise.
* tests/accounts.scm ("allocate-passwd")
("allocate-passwd with previous state"): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-07 20:05:09 +0100'>2019-03-07</span></td><td><a href='/guix/commit/gnu/system/accounts.scm?id=6061d01512081c93c53fdd1d4302b36696403061'>activation: Operate on &lt;user-account&gt; and &lt;user-group&gt; records.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/system/accounts.scm (sexp-&gt;user-group, sexp-&gt;user-account): New
procedures.
* gnu/system/shadow.scm (account-activation): Call them in the arguments
to 'activate-users+groups'.
(account-shepherd-service): Likewise.
* gnu/build/activation.scm (activate-users+groups): Expect a list of
&lt;user-account&gt; and a list of &lt;user-group&gt;.  Replace uses of 'match' on
tuples with calls to record accessors.
(activate-user-home): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-07 20:04:02 +0100'>2019-03-07</span></td><td><a href='/guix/commit/gnu/system/accounts.scm?id=f6f67b87c08fe7b901db834c714aceaef2b62b60'>system: Add (gnu system accounts).</a><span class='msg-avail'>...<span class='msg-tooltip'>The (gnu system accounts) module is meant to be used both on the build-
and on the host-side.

* gnu/system/shadow.scm &lt;top level&gt;: Call 'default-shell'.
(&lt;user-account&gt;, &lt;user-group&gt;): Move to...
* gnu/system/accounts.scm: ... here.  New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add system/accounts.scm.
</span></span></td><td>Ludovic Courtès</td></tr>