src: use PersistentToLocal() in a few more places

Update a few more `Local<T>::New(isolate, persistent)` call sites to
`PersistentToLocal(isolate, persistent)` - the latter has a fast path
for non-weak persistent references.
src: use static_cast for void-to-T casts

Code cleanup, replace a few uses of reinterpret_cast<T*>(void_ptr) with
static_cast<T*>(void_ptr).