Harmony: Change Mock build

Include the prepackaged harmony class file. There are no longer reasons
for embedding dex files as base64.

Partially reverts commit db3fb7d7.

Bug: 116674705
Test: mmma external/apache-harmony/jdwp
Test: m apache-harmony-jdwp-tests-hostdex vogar && art/tools/run-jdwp-tests.sh --mode=host
Change-Id: I2ae775b1799f9f2e51de277fb9a660167c117ebd