tracing: Fix tracing_user config

`tracing_user.h` lost several definitions, which made
CONFIG_TRACING_USER build fail. This fixes the TRACING_USER
config & adds it to the test case.

Moreover, the idle task stack is overflow on qemu_x86, qemu_cortex_m0 &
qemu_riscv64. This makes the test fail. So this commit sets the idle
stack size to 2048 for this sample to avoid it.

Signed-off-by: Wealian Liao <WHLIAO@nuvoton.com>