test: add stress tests for initialization

Summary:

This change bangs init around like the Fonz hitting a jukebox.

Backport of core#23289.

Test Plan:

ninja check-functional

Reviewers: #bitcoin_abc, PiRK, sdulfari

Reviewed By: #bitcoin_abc, PiRK, sdulfari

Subscribers: PiRK

Differential Revision: https://reviews.bitcoinabc.org/D12598