The Vulkan implementation shouldn't depend on any of the legacy
directories. Also, changes to the environment-wide include paths
may have undesired consequences.

Bug b/116336664

Change-Id: Ied3c8f4e56994379db3518a4fbf0268451d84079
Reviewed-on: https://swiftshader-review.googlesource.com/c/21188Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>