hush testsuite: add many tests from ash testsuite

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush_test/hush-misc/heredoc4.right b/shell/hush_test/hush-misc/heredoc4.right
new file mode 100644
index 0000000..371b092
--- /dev/null
+++ b/shell/hush_test/hush-misc/heredoc4.right
@@ -0,0 +1 @@
+'$'