Performance optimization in transform node traversal.

Performance optimization in transform node traversal.

Transform node matrix calculation was modified to use the combined
matrix stack instead of matrix stack. Combined matrix stack has already
been used by clip and geometry nodes.

This improves performance because combined matrix stack stores
pointers (matrix stack stored objects). It also removes duplication of
information.

Change-Id: I1a5a2546fa9aa5a4823328dd8a321ddc42fd15a0
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>