Add TEST_REQUIRE() and __TEST_REQUIRE() to replace the myriad open coded
instances of selftests exiting with KSFT_SKIP after printing an
informational message.  In addition to reducing the amount of boilerplate
code in selftests, the UPPERCASE macro names make it easier to visually
identify a test's requirements.

Convert usage that erroneously uses something other than print_skip()
and/or "exits" with '0' or some other non-KSFT_SKIP value.

Intentionally drop a kvm_vm_free() in aarch64/debug-exceptions.c as part
of the conversion.  All memory and file descriptors are freed on process
exit, so the explicit free is superfluous.
Signed-off-by: NSean Christopherson <seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>