Demonstrate that the qapi generator doesn't deal well with
expressions that aren't up to par. Later patches will improve
the expected results as the generator is made stricter.  Only
a few of the the added tests actually behave sanely at
rejecting obvious problems or demonstrating success.

Note that in some cases, we reject bad QAPI merely because our
pseudo-JSON parser does not yet know how to parse numbers.  This
series does not address that, but when a later series adds support
for numeric defaults of integer fields, the testsuite will ensure
that we don't lose the error (and hopefully that the error
message quality is improved).
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>