x86/nVMX: Test L1 interception of #BP and #OF in the L2 guest

Int3 (#BP) and INTO (#OF) are unusual, in that they are reported as
"software exception" rather than "hardware exception" in the VM-exit
interruption information field of the VMCS.

Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>