Test and fix bug checking status of secondary multidex files.

We were accidentally returning 'false' instead of 'true' to indicate a native
multidex file with an up-to-date primary dex file checksum but out-of-date
secondary dex file checksum is out of date.

Bug: 21022815
Change-Id: I43d360ca9251d0df38ad7f8289f6ef339c0a3280
diff --git a/runtime/oat_file_assistant.cc b/runtime/oat_file_assistant.cc
index d07c09c..84d9505 100644
--- a/runtime/oat_file_assistant.cc
+++ b/runtime/oat_file_assistant.cc
@@ -417,7 +417,7 @@
           << secondary_dex_location
           << ". Expected: " << expected_secondary_checksum
           << ", Actual: " << actual_secondary_checksum;
-        return false;
+        return true;
       }
     } else {
       // If we can't get the checksum for the secondary location, we assume