Specify user defined test

Now it is possible to get the VM Trace of a single test with : ./testeth --log_level=test_suite --run_test=StateTests/userDefinedFileState --statetest <pathToTestFile> <testname>     ( for state tests)
And ./testeth --log_level=test_suite --run_test=VMTests/userDefinedFileState --vmtest <pathToTestFile> <testname> for vm tests.