fix: Race condition in SentryTracer

[philipphofmann]

📜 Description

Fix a race condition of the wasFinishCalled property in SentryTracer by using two extra synchronized blocks.

💡 Motivation and Context

The thread sanitizer tests fail on the main branch.

💚 How did you test it?

Thread sanitizer tests.

📝 Checklist

You have to check all boxes before merging:

• I reviewed the submitted code.
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (80da9d1) 89.166% compared to head (7260615) 89.213%.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #3523       +/-   ##
=============================================
+ Coverage   89.166%   89.213%   +0.047%     
=============================================
  Files          528       528               
  Lines        57532     57526        -6     
  Branches     20614     20613        -1     
=============================================
+ Hits         51299     51321       +22     
+ Misses        5315      5292       -23     
+ Partials       918       913        -5     

Files	Coverage Δ
Sources/Sentry/SentryTracer.m	96.761% <100.000%> (+0.408%)	⬆️

... and 11 files with indirect coverage changes

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1206.76 ms	1227.40 ms	20.64 ms
Size	21.58 KiB	418.58 KiB	396.99 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
5ab598f	1213.90 ms	1240.45 ms	26.55 ms
4b08ceb	1237.75 ms	1249.61 ms	11.86 ms
56ec5d0	1236.65 ms	1261.90 ms	25.25 ms
1db04d8	1250.20 ms	1258.12 ms	7.92 ms
1e065bc	1239.69 ms	1258.18 ms	18.49 ms
3437454	1225.64 ms	1234.31 ms	8.67 ms
01a28a9	1237.78 ms	1259.04 ms	21.27 ms
8919322	1231.83 ms	1255.24 ms	23.41 ms
fb53d97	1235.00 ms	1241.88 ms	6.88 ms
2ce582e	1238.98 ms	1259.66 ms	20.68 ms

App size

Revision	Plain	With Sentry	Diff
5ab598f	22.84 KiB	403.17 KiB	380.33 KiB
4b08ceb	20.76 KiB	431.99 KiB	411.23 KiB
56ec5d0	20.76 KiB	414.44 KiB	393.69 KiB
1db04d8	20.76 KiB	435.50 KiB	414.74 KiB
1e065bc	20.76 KiB	425.78 KiB	405.01 KiB
3437454	22.85 KiB	408.87 KiB	386.02 KiB
01a28a9	22.85 KiB	405.39 KiB	382.54 KiB
8919322	22.84 KiB	403.18 KiB	380.34 KiB
fb53d97	20.76 KiB	425.80 KiB	405.04 KiB
2ce582e	22.85 KiB	410.97 KiB	388.12 KiB