fix(auto-instrumentations-node): shutdown the SDK when the process exits normally

[aabmass]

Which problem is this PR solving?

Fixes #2383

Short description of the changes

Adds a one-shot beforeExit hook to call NodeSDK.shutdown(). In the event of SIGTERM and the process gracefully exiting, shutdown may be called twice. I believe the additional calls to shutdown() should no-op so that is not a concern but may make for spammy logs.

I updated the tests to capture the expected behavior

• Shutdown on SIGTERM
• Shutdown when exiting normally

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.64%. Comparing base (dfb2dff) to head (3c06297).
Report is 222 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2394      +/-   ##
==========================================
- Coverage   90.97%   90.64%   -0.34%     
==========================================
  Files         146      156      +10     
  Lines        7492     7612     +120     
  Branches     1502     1571      +69     
==========================================
+ Hits         6816     6900      +84     
- Misses        676      712      +36     

see 76 files with indirect coverage changes

[trentm]

Thanks!

[trentm]

I'll leave some time for others to review as well.