tests: counter: Extend counter_basic_api timeout

Fixes a timeout failure on the frdm_k64f board.

test_short_relative_alarm iterates 100x through a 3 tick loop, but some
platforms like frdm_k64f have a 1 second counter tick period and
therefore need more time to finish this test.

Signed-off-by: Maureen Helm <maureen.helm@nxp.com>