Blocksize Config Make Check Failures

I'm attempting to get a little bit more disk performance out of a data warehouse like PG 9.5 RC1 instance I have that is running on ZFS (recordsize=128K). When trying to make PG 9.5RC1 with --blocksize > 8 four of the make check tests are reported as failing. I'm curious as to if this is a problem with the checks or if the errors would cause problems in usage. None of the make check errors caused the server to terminate or have serious issues but I just wanted to check if anyone else had concerns.

You can see for yourself the failures with this command:
git checkout tags/REL9_5_RC1; make clean; ./configure --with-blocksize=16; make; make check

For example the select_views regression.diff shows that the explain plan changed which doesn't seem overly concerning. The tablesample failure though is more interesting. I'm not entirely sure that tablesample is working correctly though in terms of the count of data it should be returning but at least it is returning some data.

See attached for the regression.diffs.

Mike