Optimizes check for Smi range in the code generator....

Optimizes check for Smi range in the code generator.
The check whether a 32-bit signed integer is in the Smi
range is now Sign bit( value + 0x40000000 ) == 0,
done with a single cmp instruction.

Committed: http://code.google.com/p/v8/source/detail?r=1134

[Kevin Millikin (Chromium), 2009-01-23 12:20:46]

In the rest of the code we use lowercase hex digits (eg, 0xdeadbeed).