Remove it root and stem to ensure there can't be any usage of it, since
it cannot be efficiently supported by ANGLE with SwiftShader Vulkan
without major changes.

Bug: b/147536183
Bug: b/147762087
Change-Id: Ib413e7c7f8d13ee22a5201e34163f592db572d86
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/40112
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Lingfeng Yang <lfy@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>