Experimental: handle single-entry basic blocks as a special case....

Experimental: handle single-entry basic blocks as a special case.
Also, clean up fast switch jump tables.

If basic block entry labels are forward-only and they are bound with
exactly one incoming CFG edge (either a live frame and no jumps or
branches, or no live frame and a single jump or branch) then they can
be treated specially.

The body of the block is compiled with the single reaching frame, with
no extra code emitted.

The fast-case switch statements are cleaned up to use raw labels
rather than jump targets, because they do not fit the jump target
abstraction very well.

Committed: http://code.google.com/p/v8/source/detail?r=1221

[Mads Ager (chromium), 2009-02-04 10:37:56]

LGTM