When the shader contains interpolation instruction, interpolation
related data needs to be stored in the routine in order to be able
to perform the interpolation operations in the middle of running
the spirv shader.

Bug: b/171415086
Change-Id: I08fc6befdca1df92fa50326d9047926ac3417aa5
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51734Tested-by: Alexis Hétu <sugoi@google.com>
Commit-Queue: Alexis Hétu <sugoi@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>