MSVC doen't support __attribute__((unused)),
we should use JERRY_UNUSED macro instead.
Additionally removed the internal jrt.h include from
tests/unit-core/test-common.h which was layering violation.
It made JERRY_ASSERT unavailable, we should use TEST_ASSERT.
JerryScript-DCO-1.0-Signed-off-by: Csaba Osztrogonác oszi@inf.u-szeged.hu