ntdll: Remove the overly-cautious check which prevented NtSetSystemTime from changing the time by more than two minutes.

Simplify the returning of different status codes by not playing around 
with the return value from settimeofday.

crypt32: Don't ask CertGetIssuerCertificateFromStore to verify revocation status, it almost certainly doesn't do what we want.

Show that certificates are added to memory stores at the head rather
than the tail.