RFR (S) 8009575 (2nd) - Reduce Symbol::_refcount from 4 bytes to 2 bytes

[Ioi Lam]

Forgot to respond to this one:

On 06/21/2013 11:15 AM, Daniel D. Daugherty wrote:
> src/share/vm/oops/symbol.hpp
>
>     line 132: size_t sz = heap_word_size(sizeof(SymbolBase) + (length 
> > 0 ? length : 0));
>         Assuming that 'length' can't be < 0, this is more clear:
>
>         assert(length >= 0, "sanity check");
>         size_t sz = heap_word_size(sizeof(SymbolBase) + length);
>

I am not sure if some valid code path would pass in length <=0 and 
expect an empty symbol. This is unlikely, but since I am touch Symbol 
which is widely used, I don't want to take any risks. I'd rather fix 
this in another clean-up bug.

Thanks
- Ioi