These date back to e1919611 "s3-waf: more
configure tests and minor fixes" in 2010 and were not used at that time and now.

More of these should be removed but the __pwrite() test caused a timeout
on an ARM builder in Debian. It might just be a fluke but the tests are
pointless regardless.

See also 16eb8005 "build: Remove tests for
getdents() and getdirentries()"