GltfDecoderTest.ThreeMeshesOneNoMaterialMesh fails on Windows in Release mode MSVC builds.

Disabling optimizations in draco_io prevents the failure, but that's not a viable fix. It appears that there is something wrong in the code there that's causing MSVC to generate bad code in optimized builds.

This impacts only DRACO_TRANSCODER_SUPPORTED enabled builds on the Windows platform using MSVC to build Draco in release configurations. This issue does not reproduce when using the mingw gcc/g++ compilers.