Uses llvm.vcxproj generated by build/cmake.sh

Bug b/115344057

Change-Id: I09041d219f194e5ec97daad6b1b247a565909e98
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/28110
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>