ash: fix . builtin

Also, move [[ ]] comment to test.c and expand it

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash_test/ash-misc/source1.right b/shell/ash_test/ash-misc/source1.right
new file mode 100644
index 0000000..0ab7c54
--- /dev/null
+++ b/shell/ash_test/ash-misc/source1.right
@@ -0,0 +1,2 @@
+Sourced ok
+Done