benchtests: Remove verification runs from benchmark tests

The test run is unnecessary and interferes with the benchmark.  The
tests are done during make check, so they're unnecessary here.

	* benchtests/bench-memccpy.c (do_one_test): Remove checks.
	* benchtests/bench-memchr.c (do_one_test): Likewise.
	* benchtests/bench-memcpy-large.c (do_one_test): Likewise.
	* benchtests/bench-memcpy.c (do_one_test): Likewise.
	* benchtests/bench-memmove-large.c (do_one_test): Likewise.
	* benchtests/bench-memmove.c (do_one_test): Likewise.
	* benchtests/bench-memset-large.c (do_one_test): Likewise.
	* benchtests/bench-memset.c (do_one_test): Likewise.
	* benchtests/bench-string.h (test_init): Remove memsets.