This plumbing through the specialization constant for surface rotation
from ContextVk to pipeline program creation. It has not been used yet,
so expecting no real functional change. This CL also converts
lineRasterEmulation to use the same specialization constant path as
surface rotation.

Bug: b/171750979
Change-Id: Ic08c4f8bb576424d1752015e874d0977a58d78bb
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2508837
Commit-Queue: Charlie Lao <cclao@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Ian Elliott <ianelliott@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>