KVM: selftests: Test behavior of KVM_X86_DISABLE_EXITS_APERFMPERF

KVM: selftests: Test behavior of KVM_X86_DISABLE_EXITS_APERFMPERF

For a VCPU thread pinned to a single LPU, verify that interleaved host
and guest reads of IA32_[AM]PERF return strictly increasing values when
APERFMPERF exiting is disabled.

Run the test in both L1 and L2 to verify that KVM passes through the
APERF and MPERF MSRs when L1 doesn't want to intercept them (or any MSRs).

Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20250530185239.2335185-4-jmattson@google.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250626001225.744268-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>