fa9ed38 test_node: get_mem_rss fixups (MarcoFalke)

Pull request description:

  Follow up to #14522:

  * Fix math (Memory usage increase relative to previous memory usage, not final memory usage)
  * remove `shell=True`
  * assert that the node is running
  * Make it work on BSD-like systems

Tree-SHA512: fc1b4f88173914b6cb6373655cffd781044a0c146339e3fa90da03b197faa20954567a77335965b857d29d27f32661698b6a0340f0c616f643b8c4510cd360c2

…t framework update)

7b04c0a [Test] Clean duplicate connections creation in mining_pos_coldStaking.py (furszy)
15a799e [Test] MAX_PROTOCOL_MESSAGE_LENGTH PIVXified. (furszy)
0aedf35 [tests] Don't import asyncio to test magic bytes (John Newbery)
9bb5309 Refactor resource exhaustion test (Troy Giorshev)
589a780 Fix "invalid message size" test (Troy Giorshev)
8a0c12b Move size limits to module-global (Troy Giorshev)
b3391c5 Remove two unneeded tests (Troy Giorshev)
1404e68 test: Add various low-level p2p tests (furszy)
8aaf7e1 test: Remove fragile assert_memory_usage_stable (MarcoFalke)
f68e22c [Test] p2p_invalid_messages.py do not change msg.command in test_command and raise sync_with_ping timeout (furszy)
c851c0b Test framework: Wait for verack by default on every new connection (furszy)
c02e9a0 [Test] move framework subversion to string (furszy)
3472a39 Replace coroutine with async def in p2p_invalid_messages.py (Elichai Turkel)
33c7b19 net_processing: align msg checksum check properly. (furszy)
7f71b1b Hash P2P messages as they are received instead of at process-time (furszy)
215a638 test: Skip flaky p2p_invalid_messages test on macOS (Fabian Jahr)
c11f565 qa: Make swap_magic_bytes in p2p_invalid_messages atomic (MarcoFalke)
be979ad test: Fix race in p2p_invalid_messages (MarcoFalke)
6a72f0c qa: Add tests for invalid message headers (MarcoFalke)
51ddd3d Introduce p2p_invalid_messages.py test (furszy)
55a37b5 net: fix missing jump line in "Oversized message from peer.." error. (furszy)
0edfce5 test_node: get_mem_rss fixups (MarcoFalke)
6f21213 tests: add P2PConnection.send_raw_message (James O'Beirne)
ae68c6e tests: add utility to assert node memory usage hasn't increased (James O'Beirne)
8469afe test: forward timeouts properly in send_blocks_and_test (James O'Beirne)
db28a53 Skip is_closing() check when not available. (Daniel Kraft)
be9dacb tests: fixes mininode's P2PConnection sending messages on closing transport (marcoagner)
53599c8 qa: Avoid start/stop of the network thread mid-test (furszy)
688190c [qa] mininode: Expose connection state through is_connected (MarcoFalke)

Pull request description:

  Part of the deep and long net and ser work that I'm doing (and Tor v3 onion addresses support). Friend of #2359.

  Focused on the end goal of implementing the `p2p_invalid_messages` functional test which validates that invalid msg headers, msg types, oversized payloads and inventory msgs aren't accepted nor can cause a resource exhaustion. And an extra covered scenario, in `p2p_invalid_tx.py`, for the orphan pool overflow.

  Plus, to get up to the goal, had to work over the functional test framework as well.

  So.. adapted list:

  * bitcoin#9045.
  * bitcoin#13512.
  * bitcoin#13517.
  * bitcoin#13715.
  * bitcoin#13747.
  * bitcoin#14456.
  * bitcoin#14522.
  * bitcoin#14672.
  * bitcoin#14693.
  * bitcoin#14812.
  * bitcoin#15246.
  * bitcoin#15330.
  * bitcoin#15697.
  * bitcoin#16445.
  * bitcoin#17931.
  * bitcoin#17469.
  * bitcoin#18628 (only `p2p_invalid_tx.py` and `p2p_invalid_messages.py`. We don't support the other tests yet).
  * bitcoin#19177.
  * bitcoin#19264.

ACKs for top commit:
  random-zebra:
    utACK 7b04c0a and merging...

Tree-SHA512: 48d1f1a6acc24a9abce033fbf1f281ba4392147da39d118a694a09d63c3e0610cc1a29d711b434b16cc0d0e030dd9f1a89843870091b6999b862b9ab18a20679