Request for reviews (XL): 6919934: JSR 292 needs to support x86 C1

[Christian Wimmer]

> http://cr.openjdk.java.net/~never/6939930 is a full solution.
>
> 6939930: exception unwind changes in 6919934 hurts compilation speed
> Reviewed-by:

I think that is a good unified solution now, and works in my  
workspace. I have two small comments:

* LIRAssembler_sparc.cpp: There is no "stub->emit_code(this);" like in  
the x86 code

* LIR.hpp: lir_unwind can now be a LIR_Op1. In LIR.cpp you assert that  
the second operand of the current LIR_Op2 is never used, which is weird.

Christian