KVM: selftests: Add negative testcase for PEBS format in PERF_CAPABILITIES

Expand the immutable features sub-test for PERF_CAPABILITIES to verify
KVM rejects any attempt to use a PEBS format other than the host's.

Link: https://lore.kernel.org/r/20230311004618.920745-21-seanjc@google.com


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