Expand stacktrace buffer for tsan

[kiburtse]

Change the default from 2 to 4 to help with 'failed to restore the stack' situation. Also, dump stacktrace for ubsan.

What, How & Why?

☑️ ToDos

• 📝 Changelog update
• 🚦 Tests (or not relevant)
• C-API, if public C++ API changed
• bindgen/spec.yml, if public C++ API changed

[coveralls-official]

Pull Request Test Coverage Report for Build kirill.burtsev_109

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 44 unchanged lines in 12 files lost coverage.
• Overall coverage increased (+0.01%) to 91.701%

---

Files with Coverage Reduction	New Missed Lines	%
test/test_dictionary.cpp	1	99.85%
src/realm/cluster.cpp	2	80.36%
src/realm/object-store/sync/sync_manager.cpp	2	86.9%
src/realm/table_view.cpp	2	94.18%
src/realm/util/file.cpp	2	82.15%
src/realm/sync/network/network.cpp	3	89.86%
src/realm/sync/noinst/server/server.cpp	3	75.57%
src/realm/sync/transform.cpp	3	63.08%
src/realm/sync/noinst/client_impl_base.cpp	6	86.0%
test/fuzz_group.cpp	6	55.7%

Totals
Change from base Build 1863:	0.01%
Covered Lines:	231747
Relevant Lines:	252719

---

💛 - Coveralls