Do not set the --ruby.launcher in polyglotOptions

* It would fail when exec()-ing to JVM as it is an experimental option.
* We'll rely on the launcher being RUBY_HOME/bin/truffleruby on --jvm
  for now, until an API to query the launcher path is added in Launcher.

Author: eregon

src/launcher/java/org/truffleruby/launcher/RubyLauncher.java

@@ -102,10 +102,7 @@ protected List<String> preprocessArguments(List<String> args, Map<String, String
             }
 
             if (isAOT()) {
-                final String launcher = setRubyLauncher();
-                if (launcher != null) {
-                    polyglotOptions.put(OptionsCatalog.LAUNCHER.getName(), launcher);
-                }
+                setRubyLauncher();
             }
 
         } catch (CommandLineException commandLineException) {