Support for precise stepping in functions compiled before debugging was started ...

Support for precise stepping in functions compiled before debugging was started (step 1)

This change will ensure that all non-optimized code will be compiled
with debug break slots when debugging is initiated. This is handled by
scanning the heap for non-optimized functions without debug break slots and setting their code to be lazy recomplied. When the lazy recompilation happens the code will ge generated with debug break slots (if debugging is still active at that point in time).

R=svenpanne@chromium.org
Currently this is only implemented for functions which do not have activations on the stack.

BUG=
TEST=

Review URL: http://codereview.chromium.org//7839030

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9250 ce2b1a6d-e550-0410-aec6-3dcde31c8c00