tests: kernel_workq: Excluding test for qemu_rx

Excluding this test for qemu_rx because it's failing randomly
Root cause not identified yet, #92213 is created to keep track
of this
This test case is working fine on actual RX HW so issue might be
in the inside the qemu environment

Signed-off-by: Duy Nguyen <duy.nguyen.xa@renesas.com>