Remove shift-base:net-processing from ubsan suppressions

Summary:
D12344 removed the unneeded shift, so we can remove the corresponding suppression.

This concludes backport of core#23970

Test Plan:
With UBSAN:
ninja all check check-functional

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13538