SDL2 primitive shapes don't render when SDL_ttf text is rendered

**Version of emscripten/emsdk:**
```
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.3 (c06156773675b2cb437e41459c12d44bd9a8f235)
clang version 14.0.0 (https://github.com/llvm/llvm-project d8f929a567083a6b90264193f1e4476f6b77c5fe)
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /Users/tam/Developer/emsdk/upstream/bin
```

When text is rendered to the screen (via`TTF_RenderText_Blended`, `SDL_CreateTextureFromSurface`, and `SDL_RenderCopy`) all calls to SDL's primitive shapes (i.e. `SDL_RenderDrawRect`) no longer appear and the following warning is logged to the console:

```
WebGL warning: drawArraysInstanced: Vertex fetch requires 96, but attribs only supply 6.
```

This isn't an issue when building to a native platform, and has no impact on rendering textures from image surfaces.