Useless test: test_args_sum/test_args_sum_with_separator

[nickysn]

The test program in test/programs/args_sum.rb is run twice, once as a regular test test_args_sum, and a second time as a special test test_args_sum_with_separator. In the second case, the parameter -- is passed before the program's parameters, supposedly to test whether the parameters after -- are passed to the program.

Commit 53d9252 suggests that was the intention. However, it doesn't work, because:

1. both the pure and native tracers seem to pass all the extra parameters after the program name, without treating -- as anything special, i.e. it is also passed to the program as a parameter
2. the test program args_sum.rb produces the same output, when run with parameters 1 2 3 and -- 1 2 3, so the test fails to recognize whether the -- is handled by the tracer, or whether it is passed to the program