ash: add a testcase for bug 2281 (currently fails). Small code cleanups.

function                                             old     new   delta
changepath                                           195     192      -3
subevalvar                                          1204    1200      -4
readtoken1                                          3247    3240      -7
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-14)             Total: -14 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash_test/ash-vars/var_bash4.right b/shell/ash_test/ash-vars/var_bash4.right
new file mode 100644
index 0000000..33a5112
--- /dev/null
+++ b/shell/ash_test/ash-vars/var_bash4.right
@@ -0,0 +1,2 @@
+a*b-backslashstar-
+Done: 0