Load tinyexr in its own class loader

That way we can simply use whatever version we want and aren't tied to the
version of lwjgl which MC provides.

This fixes the OpenEXR export on 1.19 crashing either due to the windows
workaround or due to differing lwjgl versions (depending on OS).
And also enables OpenEXR export on MC versions using lwjgl2 (1.12.2 and below).

src/main/resources/mixins.render.replaymod.json

@@ -36,7 +36,6 @@
     //#endif
     //#if MC>=11400
     "Mixin_PreserveDepthDuringHandRendering",
-    "Mixin_WindowsWorkaroundForTinyEXRNatives",
     //#endif
     "GameRendererAccessor",
     "MainWindowAccessor",