ANDROID: pkvm: vmx: Handle the pause vmexit

The pause vmexit is handled by the pkvm hypervisor to grow the ple
window and skip the instruction. Then return back to the host KVM to
emulate pause by spin the vcpu thread.

Bug: 391539939
Test: pKVM works
Upstream-Task: 402758258

Change-Id: I37f51468fc60e3b5e10987c740197688b76f0af9
Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: Dmytro Maluka <dmaluka@google.com>