tests/qapi-schema: Drop temporary 'prefix'

Recent commit "qapi: Smarter camel_to_upper() to reduce need for
'prefix'" added a temporary 'prefix' to delay changing the generated
code.

Revert it.  This changes TestUnionEnumA's generated enumeration
constant prefix from TEST_UNION_ENUMA to TEST_UNION_ENUM_A.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240904111836.3273842-3-armbru@redhat.com>
4 files changed