Drop test_wants_user_mappings infrastructure

Drop test_wants_user_mappings infrastructure

As noted in Errata, the test_wants_user_mappings infrastructure has problems
for pv32pae environments on Xen 4.6 and earlier, if Xen leaks SMEP/SMAP
settings into the guest.

Now that all tests have moved to the new .text.user infrastructure, drop
test_wants_user_mappings.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>