Fix line endings on Windows (2nd attempt)

Author: julianhyde

testkit/src/main/java/org/apache/calcite/test/QuidemTest.java

@@ -348,7 +348,8 @@ public static class SubPlanCommand extends AbstractCommand {
             relNode = RelDecorrelator.decorrelateQuery(relNode, relBuilder);
           }
 
-          x.echo(ImmutableList.of(RelOptUtil.toString(relNode)));
+          final String s = RelOptUtil.toString(relNode);
+          x.echo(ImmutableList.copyOf(s.split(System.lineSeparator())));
         }
       } else {
         x.echo(content);