include "thread-pcs" info in stop reply

DS2 does not implement the `thread-pcs` stop reply extension documented [here](https://lldb.llvm.org/resources/lldbgdbremote.html#lldb-extensions). The `TestGdbRemoteThreadsInStopReply.test_stop_reply_contains_thread_pcs_llgs` lldb test case fails as a result.

From the lldb packet documentation:

> `thread-pcs` - `comma-sep-base16` - A list of pc values for all threads that currently exist in the process, including the thread that this `T` packet is reporting as stopped. This key-value pair will only be emitted when the `threads` key is already included in the `T` packet. The pc values correspond to the threads reported in the `threads` list. The number of pcs in the `thread-pcs` list will be the same as the number of threads in the `threads` list. lldb may request that this be included in the `T` packet via the `QListThreadsInStopReply` packet earlier in the debug session.

> Example:
> `thread-pcs:dec14,2cf872b0,2cf8681c,2d02d68c,2cf716a8;`