[coverage] Run instrumentation once for all targets, streamline command line parameters.
Review Request #3107 - Created Nov. 11, 2015 and submitted
Testing the latest cobertura code against non-trivial targets revealed a few issues...two of them are addressed here:
1) we run instrumentation once for all files to be instrumented from all targets...existing code runs it for all files x each target.
2) streamline command-line params by removing unnecessary params (i.e. auxclasspath) and using the listOfFilesToInstrument to keep the command-line short.
There will be another branch to fix-up the instrumentation classpath...these changes stand on their own tho, so keeping the review small.
Manual coverage runs against larger projects in twitter code base, also ran manually against oss pants test targets.