In Debugger::registerCodeBlock(), we should never have to jettison a code block (due to pending breakpoints or stepping mode) that is being registered. operationOptimize() should have prevented the optimizing of such code blocks in the first place. Find a way to express this with greater clarity in the code.
This fix was handled in <https://bugs.webkit.org/show_bug.cgi?id=151892>. *** This bug has been marked as a duplicate of bug 151892 ***