Fixed compound/count operations with getter-only accessor properties.

Fixed compound/count operations with getter-only accessor properties.

The underlying problem is that for compound/count operations we use the *load*
type feedback for storing, too. For normal properties this doesn't matter, but
for accessor properties we should better use the *store* type feedback, which
would be available, too. This consistent feedback usage could be guaranteed if
we removed the heavy copy-n-paste in the crankshaft code generation for
compound/count operations and assignments/property loads.

To be on the safe side, we postpone this refactoring and do a quick and easily
mergeable fix.

BUG=140083
TEST=mjsunit/regress/regress-crbug-140083.js

Committed: https://code.google.com/p/v8/source/detail?r=12252

[Michael Starzinger, 2012-08-03 09:44:31]

LGTM.