Handle possible difference between function code and activated code on preparation for break points

Handle possible difference between function code and activated code on preparation for break points

The full code activated for a function might not be the same code as
is currently the active full code for a function. There where some
asumptions in the debugger preparation for break points.

Unfortunately there is currently no regression test.

R=jkummerow@chromium.org

BUG=
TEST=

Committed: http://code.google.com/p/v8/source/detail?r=10176

[Jakob Kummerow, 2011-12-06 12:51:14]

LGTM, thanks!