SPU recompilers cannot execute code while cpu_thread::state is non-zero

[elad335]

Unlike interpreters, where call check_state() once and continue execution if theres no need to exit, recompilers will get stuck if cpu_thread::state is non-zero and check_state() didnt clear it.
This is the reason single stepping causes the SPU threads to get stuck forever on recompilers, where you had expect them atleast to step into the next code block.
Fixing this is required for #8514 to work on recompilers.