CTS API Surface Coverage Tool

Adds a few make rules to generate coverage reports that use
dexdeps to see what methods from the API are directly
called from the tests rather than using the usual approach
of using EMMA.

    make cts-test-coverage

This rule will generate coverage of the API from the test
cases in CtsTestCaseList's CTS_COVERAGE_TEST_CASE_LIST list.

    make cts-verifier-coverage

This rule will generate coverage by the CtsVerifier.

Change-Id: I28c8d825cff5b1c6b293b786e28a472059a7259a