The entries in the Changelog are dated from when those patches were created. If you look at the second entry in that Changelog it has the glibc fix white space in syslog messages patch.
The Changelog.txt file was updated at 14:10 on 10th Oct.
Based on that I took my CU171 Testing vm and moved the mine file back to 170 and then re-ran the upgrade from 170 to 171 Testing, rebooted and everything created in the log after that no longer has the additional space. So yes, it is in the latest CU171 Testing.
Of course, the logs from the intervening period will stay with the additional space but if you do an upgrade on a CU170 system then all the logs will have the correct spacing.