Windows x86_64 LLDB tests are not run as part of the Swift toolchain CI

[kendalharland]

Filing this issue for Visibility. With the help of @compnerd and a few others, I'm working on getting the LLDB tests up and running for Windows x86_64 builds of the swift toolchain. So far, I've been able to get all of the upstream llvm/llvm-project tests to build and pass locally at HEAD [issue link] save for one [link]. Using those results as a baseline, all of the swiftlang/llvm-project LLDB tests should also pass. This is an "epic" style bug that will hold the context for this project and track other child issues to run and fix the tests.

[kendalharland]

#9103 will need to be cherry picked into swiftlang/swift/stable/20230725 when it is merged.