test: add integration tests for various tenure-extend scenarios

[brice-stacks]

This adds a simple new integration test to ensure that the miner has the expected behavior when it should extend, in three different scenarios:

1. An empty Bitcoin block with no commits, even though the miner had submitted a valid commit
2. A Bitcoin block with an old commit from the previous tenure
3. An empty Bitcoin block with no commits, and the miner never submitted one.

This was in response to a stall where it seemed that a miner failed to extend its tenure after a Bitcoin block with no block commits in it. Unfortunately, it seems my test was not creative enough to find any issue and we don't have the logs from that miner.

[francesco-stacks]

LGTM!

[codecov]

Codecov Report

❌ Patch coverage is 26.47059% with 75 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.52%. Comparing base (267c7ef) to head (10c1734).
⚠️ Report is 31 commits behind head on develop.

Files with missing lines	Patch %	Lines
stacks-node/src/tests/nakamoto_integrations.rs	0.00%	72 Missing ⚠️
stacks-node/src/tests/neon_integrations.rs	90.00%	3 Missing ⚠️

❌ Your project status has failed because the head coverage (72.52%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

❗ There is a different number of reports uploaded between BASE (267c7ef) and HEAD (10c1734). Click for more details.

HEAD has 11 uploads less than BASE

Flag	BASE (267c7ef)	HEAD (10c1734)
	78	67

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6784      +/-   ##
===========================================
- Coverage    78.40%   72.52%   -5.89%     
===========================================
  Files          585      585              
  Lines       361384   361456      +72     
===========================================
- Hits        283360   262141   -21219     
- Misses       78024    99315   +21291     

Files with missing lines	Coverage Δ
stacks-node/src/tests/signer/v0.rs	21.59% <ø> (-1.27%)	⬇️
stacks-node/src/tests/neon_integrations.rs	18.38% <90.00%> (-3.47%)	⬇️
stacks-node/src/tests/nakamoto_integrations.rs	12.00% <0.00%> (-22.10%)	⬇️

... and 262 files with indirect coverage changes

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