[lldb] Add missing calls to SetStatus in CommandObjectPlatform (#197548)

Add missing calls to CommandReturnObject::SetStatus in
CommandObjectPlatform. I replaced some calls to AppendMessageWithFormatv
with AppendErrorWithFormatv because the latter implicitly sets the
status.

lldb/source/Commands/CommandObjectPlatform.cpp

diff --git a/lldb/source/Commands/CommandObjectPlatform.cpp b/lldb/source/Commands/CommandObjectPlatform.cpp
index 52b571a..82e3448 100644
--- a/lldb/source/Commands/CommandObjectPlatform.cpp
+++ b/lldb/source/Commands/CommandObjectPlatform.cpp
@@ -394,6 +394,7 @@
       if (m_option_working_dir.GetOptionValue().OptionWasSet())
         platform_sp->SetWorkingDirectory(
             m_option_working_dir.GetOptionValue().GetCurrentValue());
+      result.SetStatus(eReturnStatusSuccessFinishResult);
     } else {
       result.AppendError("no platform is currently selected");
     }
@@ -833,8 +834,8 @@
             remote_file_path, local_file_path);
         result.SetStatus(eReturnStatusSuccessFinishResult);
       } else {
-        result.AppendMessageWithFormatv("get-file failed: {0}",
-                                        error.AsCString());
+        result.AppendErrorWithFormatv("get-file failed: {0}",
+                                      error.AsCString());
       }
     } else {
       result.AppendError("no platform currently selected\n");
@@ -879,9 +880,8 @@
                                         remote_file_path.c_str(), size);
         result.SetStatus(eReturnStatusSuccessFinishResult);
       } else {
-        result.AppendMessageWithFormatv(
-            "Error getting file size of {0} (remote)",
-            remote_file_path.c_str());
+        result.AppendErrorWithFormatv("failed to get file size of {0} (remote)",
+                                      remote_file_path.c_str());
       }
     } else {
       result.AppendError("no platform currently selected\n");
@@ -1152,6 +1152,7 @@
         if (rebroadcast_first_stop) {
           assert(first_stop_event_sp);
           process_sp->BroadcastEvent(first_stop_event_sp);
+          result.SetStatus(eReturnStatusSuccessFinishNoResult);
           return;
         }
 
@@ -1184,6 +1185,8 @@
           result.SetStatus(eReturnStatusSuccessFinishNoResult);
           return;
         }
+        if (result.GetStatus() != eReturnStatusFailed)
+          result.SetStatus(eReturnStatusSuccessFinishNoResult);
       } else {
         result.AppendError("'platform process launch' uses the current target "
                            "file and arguments, or the executable and its "
@@ -1503,6 +1506,8 @@
               ostrm.EOL();
             }
           }
+          if (result.GetStatus() != eReturnStatusFailed)
+            result.SetStatus(eReturnStatusSuccessFinishResult);
         } else {
           // Not connected...
           result.AppendErrorWithFormatv("not connected to '{0}'",