rsx: Compile shaders when CELL is not running

[elad335]

Previously RSX waited until PPU called sys_rsx syscalls to compile shaders, then it let SPU and PPU run at fullspeed when doing so which can choke CPUs with not many threads.
This is also a bug which can cause timeout assertations from CELL side at startup due to RSX not responding for long period of time at startup when compiling shaders. (emulation must not observe the time in which RSX compiles shaders)
To solve it compile shaders before CELL is running, do not wait for PPU to execute some syscall. In fact now PPU will wait until RSX has been fully initialized to execute any stuff.