C2: pass compilation options as structure

Currently we pass several compilation options as separate arguments:

Compile C(env, target, entry_bci, subsume_loads, do_escape_analysis, eliminate_boxing, do_locks_coarsening, install_code, directive);

Originally we had only `subsume_loads` option but we added more later and we may add more.

I suggest to add new `Options` class to pass these values into `Compile`.