hush: fix heredoc handling in the "cmd <<EOF ;<newline>" case

function                                             old     new   delta
parse_stream                                        2759    2787     +28

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush_test/hush-heredoc/heredocA.right b/shell/hush_test/hush-heredoc/heredocA.right
new file mode 100644
index 0000000..7326d96
--- /dev/null
+++ b/shell/hush_test/hush-heredoc/heredocA.right
@@ -0,0 +1 @@
+Ok