Fix type alias compilation issue on Windows.
Fix type alias compilation issue on Windows.

With Visual Studio 2015, the Traits type alias is not considered
within scope yet for the constructor's argument list. Instead Use
the template argument directly.

BUG=swiftshader:7

Change-Id: I677f5bed1a4749aba921a23ed5b1466431147069
Reviewed-on: https://chromium-review.googlesource.com/379915
Reviewed-by: Jim Stichnoth <46a13f57ad465cec7f48cfe1a20c394bb659ab25@chromium.org>
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

google/swiftshader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader