Remove PersistentBase::ClearAndLeak
Remove PersistentBase::ClearAndLeak

Embedders that used this method to be able to store a Persistent in a
container should use one of the containers in v8-util.h instead.

Other uses are no longer supported.

BUG=none
R=dcarney@chromium.org
LOG=y

Review URL: https://codereview.chromium.org/635513002

git-svn-id: f98b9d40cb02301bc76fa9e1b46ee668158567fd@24436 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh