ash: add all hush parsing tests to ast tests

All pass.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

shell/ash_test/ash-parsing/quote3.tests

@@ -0,0 +1,21 @@
+empty=''
+
+echo 'Testing: in ""'
+for a in ""; do echo ".$a."; done
+
+echo 'Testing: in '"''"
+for a in ''; do echo ".$a."; done
+
+echo 'Testing: in $empty'
+for a in $empty; do echo ".$a."; done
+
+echo 'Testing: in $empty""'
+for a in $empty""; do echo ".$a."; done
+
+echo 'Testing: in $empty'"''"
+for a in $empty''; do echo ".$a."; done
+
+echo 'Testing: in "$empty"'
+for a in "$empty"; do echo ".$a."; done
+
+echo Finished