Detect array types as alternate branches, and turn the JSON list into
a QAPISchemaArrayType.  Array types in an alternate are represented with
QTYPE_QLIST in the type field.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220321164243.200569-2-pbonzini@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>