Fix for bug 351257: type feedback vector initialization issue.

Fix for bug 351257: type feedback vector initialization issue.

The feedback vector is stored in the shared function info, and there
is an effort to reuse it when re-running full code generation as a
prelude to creating optimized code. However we shouldn't reuse the
vector for lazily compiled methods on first compile, as scoping analysis
can change the allocation of vector slots.

BUG=351257
LOG=N
R=danno@chromium.org, bmeuer@chromium.org

Review URL: https://codereview.chromium.org/196723003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19854 ce2b1a6d-e550-0410-aec6-3dcde31c8c00