tests/kernel: timer_api: Remove build_only tickless variant

'build_only' directive may not be justified here and
prevent to see issue when running the test.

Similarly to non tickless version exclude qemu_x86_coverage
and qemu_cortex_m0 platforms.
It was actually tested failed on qemu_cortex_m0, no error
reported on qemu_x86_coverage, but removed to be safe on that side
as well.

Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
1 file changed