Temporarily(?) weaken new pg_createsubscriber test on Windows.

Don't include double-quotes (") in the generated database names
on Windows.  Doing so tickles a bug in older versions of IPC::Run,
which fail to quote command line arguments correctly for that
platform.  Possibly we can revert this after updating affected
buildfarm animals.

Discussion: https://postgr.es/m/2509767.1719773880@sss.pgh.pa.us

src/bin/pg_basebackup/t/040_pg_createsubscriber.pl

@@ -29,6 +29,10 @@ sub generate_db
 	}
 
 	$dbname .= $suffix;
+
+	# Old IPC::Run mis-quotes command line arguments containing '"' on Windows
+	$dbname =~ tr/\"//d if ($windows_os);
+
 	$node->command_ok(
 		[ 'createdb', $dbname ],
 		"created database with ASCII characters from $from_char to $to_char");