resource: Handle lists correctly in item_matches

We want to handle lists in the same way as we handle them in combine().
Without this commit, reserve()->find() failed to match objects
containing dictionaries inside lists correctly (such as trx configs).

A few attributes are added to trx_list of some resources in
suite_test/resources.conf to show a case in which resource reservation
would fail without this patch. It failed because before this patch,
dictionaries inside lists are compared to be equal instead of being
compared element by element to see if one dictionary is a subset of the
other one (for each element in the lists).

Change-Id: I8588d5b788b9f74a9cc84b8bdcb049921788bb48
diff --git a/selftest/resource_test.ok b/selftest/resource_test.ok
index d366cf9..416e477 100644
--- a/selftest/resource_test.ok
+++ b/selftest/resource_test.ok
@@ -243,3 +243,9 @@
 
 ~~~ end: currently reserved
 
+- item_matches:
+1st subset matches correctly, pass
+2nd subset matches correctly, pass
+3rd subset should not match, pass
+3rd subset should not match, pass
+4th subset should not match, pass