Squashed 'external/devlib/' changes from 5b04f1f6b..2e5efb815

2e5efb815 ftrace: Add write-to-disk mode
ee9317ec1 connection: Support all signals in BackgroundCommand.send_signal()
b9d2317a6 utils/asyn: Replace nest_asyncio with greenlet
7e0c3e862 Revert "utils/asyn: Replace nest_asyncio with greenback"
3ca1bb105 utils/asyn: Replace nest_asyncio with greenback
83a566a49 utils/asyn: Factor out the calls to asyncio.run
54b39a403 target: Allow reuse of a connection once the owning thread is terminated
11fc36e7c tests: Add tests for nested async support
REVERT: 5b04f1f6b ftrace: Add write-to-disk mode
REVERT: 1ede4c92f connection: Support all signals in BackgroundCommand.send_signal()
REVERT: 332d32bf0 utils/asyn: Ensure the async generators inside context managers are fully consumed on a single event loop
REVERT: d0f2cec9d utils/asyn: Replace nest_asyncio with greenlet
REVERT: afa490d36 Revert "utils/asyn: Replace nest_asyncio with greenback"
REVERT: d97c798a5 utils/asyn: Replace nest_asyncio with greenback
REVERT: 071cc6f3c utils/asyn: Factor out the calls to asyncio.run
REVERT: 103428de6 target: Allow reuse of a connection once the owning thread is terminated
REVERT: 58613fc79 tests: Add tests for nested async support

git-subtree-dir: external/devlib
git-subtree-split: 2e5efb8152b0fdeed74c90a70b8ead1a28d46b5b