tests: Dont run coverage for select test cases.

Disabled the CONFIG_COVERAGE for benchmarks and other tests.
This is needed because it interferes with normal behavior of the
test case.

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>