This is next step after JDK-8214309.

Introduce new make target(s) to run tests with code coverage.

One needs to have an instrumented build to collect code coverage. Next sequence of steps should be performed:
1. if a JCov network grabber running
  1.1. stop it
  1.2. wait for it to stop
2. start JCov network grabber in background
3. wait for it to start
4. run tests as usual only against the instrumented build
  4.1. Supply additional memory options (-Xms, -Xmx)
5. stop JCov network grabber
6. wait for it to stop
7. generate report

Both raw coverage data (a.k.a. result.xml) and the report should be handles as bundles.