tests: Add --csv option to bench-slope.

* tests/bench-slope.c (STR, STR2): New.
(cvs_mode): New.
(num_measurement_repetitions): New.  Replace use of
NUM_MEASUREMENT_REPETITIONS by this.
(current_section_name, current_algo_name, current_mode_name): New.
(bench_print_result_csv): New.
(bench_print_result_std): Rename from bench_print_result.
(bench_print_result): New. Divert depending on CSV_MODE.
(bench_print_header, bench_print_footer): take care of CSV_MODE.
(bench_print_algo, bench_print_mode): New.  Use them instead of
explicit printfs.
(main): Add options --csv and --repetitions.

Signed-off-by: Werner Koch <wk@gnupg.org>
tests: Speed up benchmarks in regression test mode.

* tests/tsexp.c (check_extract_param): Fix compiler warning.
* tests/Makefile.am (TESTS_ENVIRONMENT): Set GCRYPT_IN_REGRESSION_TEST.
* tests/bench-slope.c (main): Speed up if in regression test mode.
* tests/benchmark.c (main): Ditto.

Signed-off-by: Werner Koch <wk@gnupg.org>