Profile on timeout

[IanButterworth]

Adds a SIGUSR1/SIGINFO profile before timeout cancellation by intercepting the cancellation signals.

There may be a better way to implement this.. ideally gh would provide a way to natively do this before sending the cancellation signal, but I didn't find anything.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (013f11f) to head (198ed29).

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #155   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines            2         2           
=========================================
  Hits             2         2           

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[IanButterworth]

macOS is hanging on startup on julia nightly. This is what we see with this PR (with buildpkg disabled so it doesn't hang there)

======================================================================================
Information request received. A stacktrace will print followed by a 1.0 second profile.
--trace-compile is enabled during profile collection.
======================================================================================
signal (29): Information request: 29
__psynch_cvwait at /usr/lib/system/libsystem_kernel.dylib (unknown line)
unknown function (ip: 0x0) at (unknown file)
__psynch_mutexwait at /usr/lib/system/libsystem_kernel.dylib (unknown line)
unknown function (ip: 0x0) at (unknown file)
==============================================================
Profile collected. A report will print at the next yield point.
Disabling --trace-compile
==============================================================
[2411] signal 15: Terminated: 15
in expression starting at none:0
__psynch_cvwait at /usr/lib/system/libsystem_kernel.dylib (unknown line)
unknown function (ip: 0x0) at (unknown file)
__psynch_mutexwait at /usr/lib/system/libsystem_kernel.dylib (unknown line)
unknown function (ip: 0x0) at (unknown file)
Allocations: 1 (Pool: 1; Big: 0); GC: 0
Error: The operation was canceled.