[cxx-interop] Do not add base class members that cause lookup ambigui…

[hyp]

…ties with a derived class member of the same name

Fixes #66323

(cherry picked from commit 11d7d58)

• Explanation: Swift's clang importer adds base class members into a derived class when such a derived C++ class is imported into Swift. However, the importer did not check if the added member could cause an ambiguity between another member in the derived class and the added base member. This caused ambiguity errors when trying to call shadowed or reimplemented base class members from derived class in Swift. This change resolves this by detecting ambiguous base members using their arity and not adding them into the derived class when they conflict with another derived member.
• Scope: C++ interop, clang importer, base class member import.
• Risk: Medium, affects how base class members are imported. Tested on some adopters without issues.
• Testing: Unit tests, adopter testing.
• Original PR: [cxx-interop] Do not add base class members that cause lookup ambigui… #67178

[hyp]

@swift-ci please test

[hyp]

@swift-ci please test source compatibility