remove vpath test for user dir the test was broken and fixing is insane

remove vpath test for user dir the test was broken and fixing is insane

so this test fails on windows as getuid isn't there... so this fixes
the windows bild: fix T7728 ... but it also would have failed if $HOME
didn't match what was in the passwd file, and other fallback cases if
they were triggered.

but ... to make this test stay it would have to also change the logic
- check $HOME env first, then pwent entry, if that fails /tmp/UID and
if that fails use /tmp ... the test would effectively be a copy &
paste of the vpath code at which point this is really pointless where
testing is copying the exact (or almost exat) same code into the test.
this is ignoring the #ifdef fun of martching ifdefs that vary on
windows.

the problem is this kind of api is defined very much by the system it
runs on and the environment and situation, so the test has to be as
complex. realistically, instead of copying & pasting the code across
and now having 2 bits of code to possibly mantain (change the lib src
then the test needs changes too as it's a copy & paste), it's just
saner not to have a test for this kind of siutation and accept the
reality of the situation.

@fix