Attribute location wasn't working properly.
This faulty constructor explains why.

Change-Id: I7701ad316df0684ad02ed405bd2905d56a848bd6
Reviewed-on: https://swiftshader-review.googlesource.com/8328Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>