RCORE-2126 Clear incomplete bootstraps when the connection is established

[danieltabacaru]

What, How & Why?

Clear incomplete bootstraps when the connection is established. Additionally, prevent re-processing pending bootstraps in the same session if it failed once already.

Fixes #7707.

☑️ 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 daniel.tabacaru_937

Details

• 49 of 50 (98.0%) changed or added relevant lines in 4 files are covered.
• 67 unchanged lines in 16 files lost coverage.
• Overall coverage increased (+0.02%) to 91.124%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/realm/sync/noinst/client_impl_base.cpp	2	3	66.67%

Files with Coverage Reduction	New Missed Lines	%
src/realm/index_string.cpp	1	85.32%
src/realm/sort_descriptor.cpp	1	94.06%
src/realm/sync/network/websocket.cpp	1	72.2%
test/test_table.cpp	1	99.51%
src/realm/array_blobs_big.cpp	2	98.58%
src/realm/object-store/shared_realm.cpp	2	91.9%
src/realm/table_view.cpp	2	92.99%
src/realm/mixed.cpp	3	86.46%
src/realm/query_expression.hpp	3	93.85%
test/test_thread.cpp	3	66.14%

Totals
Change from base Build 2615:	0.02%
Covered Lines:	217244
Relevant Lines:	238404

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💛 - Coveralls

[danieltabacaru]

@mpobrien Merging this PR will most likely break CI because baas is running out of memory. Is there something we can do on the baas side to fix this? fyi, we're using a baasaas image from sept 8th.