Makes ToposortStructs() return consistent results This patch introduces a step in ToposortStructs() that sorts the nodes by name. Doing this ensures consistent results between calls. Without this, the order depends upon the pointer value, which varies depending upon when called. Ensuring consistent results for the same input is important for other parts of this code that use the string as key. Bug: chromium:1423136 Change-Id: I19f053df5cf86c81b800056e86b742d8c34af7d4 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4357255 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Scott Violet <sky@chromium.org>