Add deduping for string data and debug infos

Add multidex deduping of string data and debug info data.
Code items are still not deduped since they do not work well with
dex2oat unloading.

Reduces dex size by average of 2.96% on golem compile benchmarks.

Test: test-art-host
Bug: 63756964

Change-Id: I3f358779820adcedebf72c2ad28c367926b72ceb