always re-direct output (microsoft#912)

Fixes microsoft#710

Author: DonJayamanne

src/client/debugger/DebugClients/LocalDebugClient.ts

@@ -157,15 +157,12 @@ export class LocalDebugClient extends DebugClient<LaunchRequestArguments> {
  }
  // tslint:disable-next-line:member-ordering
  protected buildLauncherArguments(): string[] {
- let vsDebugOptions = ['RedirectOutput'];
+ const vsDebugOptions = ['RedirectOutput'];
  if (Array.isArray(this.args.debugOptions)) {
- vsDebugOptions = this.args.debugOptions.filter(opt => VALID_DEBUG_OPTIONS.indexOf(opt) >= 0);
+ this.args.debugOptions.filter(opt => VALID_DEBUG_OPTIONS.indexOf(opt) >= 0)
+ .forEach(item => vsDebugOptions.push(item));
  }
 
- // Include a dummy value, to ensure something gets sent.
- // Else, argument positions get messed up due to an empty string.
- vsDebugOptions = vsDebugOptions.length === 0 ? ['DUMMYVALUE'] : vsDebugOptions;
-
  const programArgs = Array.isArray(this.args.args) && this.args.args.length > 0 ? this.args.args : [];
  if (typeof this.args.module === 'string' && this.args.module.length > 0) {
  return [vsDebugOptions.join(','), '-m', this.args.module].concat(programArgs);