tests: network reconnect after network provider shutdown/crash
tests: network reconnect after network provider shutdown/crash

QubesOS/qubes-issues#3642

QubesOS/qubes-core-admin,marmarek/qubes-core-admin,marmarek/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,QubesOS/qubes-core-admin