[lldb][Type Completion] Load C++ methods lazily from DWARF#8579

Michael137 merged 2 commits intoswiftlang:stable/20230725swiftlang/llvm-project:stable/20230725from

Michael137:lldb/type-completion-rework/lazy-method-loadingMichael137/llvm-project:lldb/type-completion-rework/lazy-method-loadingCopy head branch name to clipboard