message: Prevent crashes when framing zero length command output
  issue
diff: @@ -1169,7 +1169,9 @@ export class EtTerminal extends ThemeableElementBase implements AcceptsKeybindin
  this._disconnectActiveTerminalViewer();
  // Extract the output of the failed command.
  + if (moveTextLines != null && moveTextLines.length > 0) {
  this._lastCommandTerminalViewer.deleteLines(this._lastCommandTerminalLine);
  + }
  this._lastCommandTerminalViewer = null;
  // Append our new embedded viewer.
  @@ -1187,7 +1189,7 @@ export class EtTerminal extends ThemeableElementBase implements AcceptsKeybindin
  outputTerminalViewer.setReturnCode(returnCode);
  outputTerminalViewer.setCommandLine(this._lastCommandLine);
  outputTerminalViewer.setUseVPad(false);
  - if (moveTextLines !== null) {
  + if (moveTextLines !== null && moveTextLines.length > 0) {
  outputTerminalViewer.setTerminalLines(moveTextLines);
  }
  outputTerminalViewer.setEditable(true);
  