Missing resources in `testrendertarget` test

[fjtrujy]

Description

The test example testrendertarget tries to load the icon-alpha.bmp file, which is not in the repo.
I have tried to find it in the git history, in case it was deleted by mistake, but I couldn't find it.

https://github.com/libsdl-org/SDL/blob/SDL2/test/testrendertarget.c#L249

I was checking if draw composite was working fine for the PSP port that I'm doing here #13314

Cheers

[slouken]

I have no idea what this was supposed to do. I'll take a look for 3.4.0.

[slouken]

This was added in SDL-mirror/SDL@4862c1f, and I never committed the icon-alpha.bmp that's listed there.

[slouken]

Fixed, thanks!