selftests/kvm: add missing executables to .gitignore

Fixes: 18178ff8 ("KVM: selftests: add Enlightened VMCS test")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/.gitignore

 /x86_64/cr4_cpuid_sync_test
+/x86_64/evmcs_test
 /x86_64/platform_info_test
 /x86_64/set_sregs_test
 /x86_64/sync_regs_test