d3d9: Add a render target test

[Ivan Gyurdiev]

H. Verbeet wrote:
> On 20/12/06, H. Verbeet <hverbeet at gmail.com> wrote:
>> This time as part of the device.c test.
>>
>> Changelog:
>>   - Add a render target test
>>
> Use the attached patch instead, the previous version doesn't apply.
This test really belongs in stateblock.c, along with every other set 
<--> get test if you ask me, that's what the framework there was written 
for.

It might be kind of a pain to get this particular one to work though, 
since changing the rendertarget is currently considered an "event", 
across which all other set/get tests are ran, but I'm sure it's 
possible. The question of whether stateblocks track render targets 
should be answered eventually...