transpose is now implemented for dynamic
variables. All NxN transpose dEQP tests pass.
There's still an issue with some NxM matrices,
but it seems to be unrelated to this code.

Change-Id: Ie422706d0085c85fa6fc9a95dc21bb441dcddfe8
Reviewed-on: https://swiftshader-review.googlesource.com/3284Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>