Remove thread anotations from rcollection

Summary: They do not work because access to the variable is always doen through the view. What we actually want to check is that the view is alive and no reference outlive it, but the current annotations do not do anything for this.

Test Plan:

ninja all check

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D7882