Revert "Set tls->context.valid to FALSE if a thread is suspended in n…

…ative code. Fixes #1540."

This reverts commit 5ddbe31.

Revert this as its incorrect, and causes a regression (#14058).

mono/mini/debugger-agent.c

@@ -2480,8 +2480,6 @@ thread_interrupt (DebuggerTlsData *tls, MonoThreadInfo *info, void *sigctx, Mono
 				/* Already terminated */
 				return TRUE;
 
-			tls->context.valid = FALSE;
-
 			/*
 			 * We are in a difficult position: we want to be able to provide stack
 			 * traces for this thread, but we can't use the current ctx+lmf, since
@@ -2515,9 +2513,9 @@ thread_interrupt (DebuggerTlsData *tls, MonoThreadInfo *info, void *sigctx, Mono
 				tls->async_state.unwind_data [MONO_UNWIND_DATA_LMF] = data.lmf;
 				tls->async_state.unwind_data [MONO_UNWIND_DATA_JIT_TLS] = tls->thread->jit_data;
 			} else {
-				/* No managed frames */
 				tls->async_state.valid = FALSE;
 			}
+
 			mono_memory_barrier ();
 
 			tls->suspended = TRUE;