Concurrency-aware debugging with Embedded Swift platform runtimes

Hello all, Following the earlier discussion with @felipepiovezan in the Multicore Concurrency thread and his follow-up on swiftlang/swift#91047, I wanted to split Embedded Swift debugger support into a dedicated discussion. The original question was how LLDB can determine which Swift task is executing on each thread. Since then, the Embedded Concurrency implementation has changed in a way that makes the question more general. Embedded now builds Concurrency against the Embedded Threading back...