Before rewriting the error recovery code to work in a push parsing
setup, make sure that we have tests for it.
Cover various cases of invalid JSON, to check that structural
recovery based on balanced brackets and braces works; and
lexer-based recovery which documents "\f" as a sure fire
way to reset the lexer.
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>