We should be changing to the internal object representation ASAP
in the API and not carry around handles when it's trivial not to.

Bug: b/116336664

Change-Id: I21de3421fd3e72f3402f2d7cefe1a3dd22c87045
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/32850
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>