Guide preservation on buffer removal

[povik]

Describe the bug

On buffer removal nets are re-routed and old routing is forgotten.

Expected Behavior

Exceptions apply but we expect old routing on the input and output side of the removed buffer to be used for the newly merged net.

It looks like this broke in #8839 as can be seen by the change in remove_buffers1.segsok and remove_buffers2.segsok. The segments no longer follow the buffer positions.

Environment

.

To Reproduce

See remove_buffers1 and remove_buffers2 tests in grt

Relevant log output

Screenshots

No response

Additional Context

No response

[povik]

@jhkim-pii Do you perhaps remember which change in #8839 prompted the updating of grt tests?

[jhkim-pii]

I sent you the details of the previous discussion by email.