chore(build): revert to sdl2

vendor/sdl-3.0.0/test/README

@@ -1,48 +0,0 @@
-
-These are test programs for the SDL library:
-
-	checkkeys	Watch the key events to check the keyboard
-	loopwave	Audio test -- loop playing a WAV file
-	testsurround	Audio test -- play test tone on each audio channel
-	testaudioinfo	Lists audio device capabilities
-	testerror	Tests multi-threaded error handling
-	testfile	Tests RWops layer
-	testgl		A very simple example of using OpenGL with SDL
-	testiconv	Tests international string conversion
-	testkeys	List the available keyboard keys
-	testloadso	Tests the loadable library layer
-	testlocale  Test Locale API
-	testlock	Hacked up test of multi-threading and locking
-	testmouse	Tests mouse coordinates
-	testmultiaudio	Tests using several audio devices
-	testoverlay	Tests the overlay flickering/scaling during playback.
-	testplatform	Tests types, endianness and cpu capabilities
-	testsem		Tests SDL's semaphore implementation
-	testshape	Tests shaped windows
-	testsprite	Example of fast sprite movement on the screen
-	testthread	Hacked up test of multi-threading
-	testtimer	Test the timer facilities
-	testver		Check the version and dynamic loading and endianness
-	testwm		Test window manager -- title, icon, events
-	torturethread	Simple test for thread creation/destruction
-	gamepadmap   Useful to generate Game Controller API compatible maps
-
-
-
-This directory contains sample.wav, which is a sample from Will Provost's
-song, The Living Proof:
-
-     From the album The Living Proof
-     Publisher: 5 Guys Named Will
-     Copyright 1996 Will Provost
-
-You can get a copy of the full song (and album!) from iTunes...
-
-    https://itunes.apple.com/us/album/the-living-proof/id4153978
-
-or Amazon...
-
-    http://www.amazon.com/The-Living-Proof-Will-Provost/dp/B00004R8RH
-
-Thanks to Will for permitting us to distribute this sample with SDL!
-