Tor should display chutney warnings during 'make test-network-all'

[teor]

This already works for 'make test-network', pending the fix in #21562.
But 'make test-network-all' redirects the chutney warnings to a log file, and we want to show a short summary after each test that logs interesting warnings.

Putting this in 0.3.0 because it will help us diagnose some outstanding bugs in 0.3.0.

[teor]

The output looks like:

PASS: single-onion
Detail: chutney/tools/warnings.sh /Users/twilsonb/tor/tor-030/../chutney/net/nodes.1488208645
Warning: Bug:     0   tor                                 0x000000010ab9e5b9 log_backtrace + 73 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     1   tor                                 0x000000010abfdc52 tor_bug_occurred_ + 450 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     10  tor                                 0x000000010a9d7f51 do_main_loop + 2401 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     11  tor                                 0x000000010a9e0b94 tor_main + 612 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     12  tor                                 0x000000010a6f9b4b main + 27 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     13  libdyld.dylib                       0x00007fffc6859255 start + 1 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     2   tor                                 0x000000010a99686a entry_guard_pick_for_circuit + 538 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     3   tor                                 0x000000010a9a93bd guards_choose_guard + 317 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     4   tor                                 0x000000010a7721b0 circuit_establish_circuit + 2480 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     5   tor                                 0x000000010a7e2eaa circuit_launch_by_extend_info + 922 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     6   tor                                 0x000000010a7dbf04 circuit_build_needed_circs + 3652 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     7   tor                                 0x000000010a9d90a4 second_elapsed_callback + 1476 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     8   libevent-2.1.6.dylib                0x000000010b3a8127 event_process_active_single_queue + 1262 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug:     9   libevent-2.1.6.dylib                0x000000010b3a49d6 event_base_loop + 1189 (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: Bug: Non-fatal assertion !(!guard_has_descriptor(guard)) failed in select_entry_guard_for_circuit at src/or/entrynodes.c:1845. Stack trace: (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2
Warning: tor_bug_occurred_: Bug: src/or/entrynodes.c:1845: select_entry_guard_for_circuit: Non-fatal assertion !(!guard_has_descriptor(guard)) failed. (on Tor 0.3.0.3-alpha-dev 73879aa5b686cf44) Number: 2

The detailed warnings are in test_network_log/*.log, and the first line contains the full path of the nodes directory, and a command to identify the node that had the warning.

[teor]

Please see my branch feature21570-030, which also includes the changes from #21562.
It depends on the chutney changes from #21571 and #21572, in commit 2ee9231 or later.
(If you don't have these changes, it will nag you to upgrade.)

[nickm]

lgtm. merging this.