KVM: selftests: Use GUEST_FAIL() in ARM's arch timer helpers

Use GUEST_FAIL() in ARM's arch timer helpers now that printf-based
guest asserts are the default (and only) style of guest asserts, and
say goodbye to the GUEST_ASSERT_1() alias.

Link: https://lore.kernel.org/r/20230729003643.1053367-35-seanjc@google.com


Signed-off-by: Sean Christopherson <seanjc@google.com>