[cherry-pick] [lldb][test] import-std-module: switch to USE_LIBCPP on Linux

[Michael137]

This fixes the following swift/release/6.0 Ubuntu CI test failures:

  lldb-api :: commands/expression/import-std-module/deque-dbg-info-content/TestDbgInfoContentDequeFromStdModule.py
  lldb-api :: commands/expression/import-std-module/list-dbg-info-content/TestDbgInfoContentListFromStdModule.py
  lldb-api :: commands/expression/import-std-module/vector-dbg-info-content/TestDbgInfoContentVectorFromStdModule.py

(cherry picked from commit https://github.com/swiftlang/llvm-project/commit/adf44d5c3ea03569f019740e1140c3205810b3fa) (cherry picked from commit https://github.com/swiftlang/llvm-project/commit/2bcab9ba7139cfa96c85433fa85b29c8a6d7008b)

[Michael137]

@swift-ci test