Allow source debugger reconnection (#1667)

Allow to wait for a new debugger connection once the previous one
is disconnected:
- when receiving a detach command
- when the client socket is closed (for example, lldb process is killed)

core/iwasm/libraries/debug-engine/debug_engine.h

@@ -12,6 +12,7 @@
 
 typedef enum WASMDebugControlThreadStatus {
     RUNNING,
+    DETACHED,
     STOPPED,
 } WASMDebugControlThreadStatus;
 
@@ -185,6 +186,9 @@ wasm_debug_instance_interrupt_all_threads(WASMDebugInstance *instance);
 bool
 wasm_debug_instance_continue(WASMDebugInstance *instance);
 
+bool
+wasm_debug_instance_detach(WASMDebugInstance *instance);
+
 bool
 wasm_debug_instance_kill(WASMDebugInstance *instance);