[lldb] Look for lldb-dap instead of lldb-vscode in the toolchain

[JDevlieghere]

The LLDB Debug Adaptor Protocol implementation was renamed from lldb-vscode to lldb-dap [1]. This commit updates the VSCode plugin to look for lldb-dap instead of lldb-vscode in the toolchain.

[1] https://discourse.llvm.org/t/rfc-rename-lldb-vscode-to-lldb-dap/74075

[JDevlieghere]

• I haven't cherrypicked the upstream commit to any of the Swift branches yet.
• I'd like to avoid having to add fallback logic to find both lldb-dap and lldb-vscode. It seems like the latter is only packaged with the Windows toolchain for now. If I cherrypick the rename to the 5.10 branch, does it sound reasonable to only look for lldb-dap? (@adam-fowler, @compnerd)

[compnerd]

@JDevlieghere we are using the old name with the 5.9 toolchain already, we will need the fallback I fear.

[adam-fowler]

I'd like to avoid having to add fallback logic to find both lldb-dap and lldb-vscode

No it's not ideal, but as @compnerd says it is already being used in Windows.

I don't know how many people are using it though. They could fall back to CodeLLDB for 5.9 maybe. The integration with lldb-vscode is only in a prerelease of the extension. Although changing it would mess with my release schedule slightly. I was hoping to do a full release with it being available. Managing multiple release branches is a pain. It would seem odd doing a full release of the extension with it using an executable not available in a swift release.

I would prefer if we had the fallback. It's not like the extension doesn't have tests for different swift versions elsewhere.

[adam-fowler]

I'm happy to do the additional fallback work

[adam-fowler]

@compnerd we could do this based on swift version. If we are using 5.9 look for lldb-vscode, otherwise look for lldb-dap. That would mean we would need an updated 5.10 toolchain before this was included in a release though. What do you think?

[compnerd]

Yeah, that seems reasonable. The 5.10 toolchain is waiting on @shahmishal as we can no longer generate the toolchain Azure due to the dependency on the swift toolchain due to macros.

[shahmishal]

You can track the work here for Windows nightly toolchain - swiftlang/swift#69484