tests/qapi-schema: Rename tests from data- to args-

Since every schema entity has 'data', the data- prefix conveys no
information.  These tests actually exercise commands.  Only commands
have arguments, so change the prefix to to args-.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

tests/qapi-schema/args-member-array.json

@@ -0,0 +1,4 @@
+# valid array members
+{ 'enum': 'abc', 'data': [ 'a', 'b', 'c' ] }
+{ 'struct': 'def', 'data': { 'array': [ 'abc' ] } }
+{ 'command': 'okay', 'data': { 'member1': [ 'int' ], 'member2': [ 'def' ] } }