Move the address space ID check that is performed when iterating over
roots into the macro helpers to consolidate code.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210326021957.1424875-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>