tests: Add feature to skip benchmarks.
* tests/benchmark.c (main): Add feature to skip the test. * tests/bench-slope.c (main): Ditto. (get_slope): Repace C++ style comment. (double_cmp, cipher_bench, _hash_bench): Repalce system reserved symbols.
During development a quick run of the regression is often useful,
however the benchmarks take a lot of time and thus this feature
allows to skip theses tests.
- Signed-off-by: Werner Koch <wk@gnupg.org>