C++: Fix queries after shared guards #3249

Job	Run time
Run Guideline Recategorization tests	14s
Run release tests	14s
Prepare supported CodeQL environment matrix	5s
Run analysis report tests (2.20.7, codeql-cli/v2.20.7, codeql-bundle-v2.20.7)	5m 27s
	6m 0s

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