[libcxx] Fix vector annotator size increase in `vector::insert(pos, count, value)`

[EricWF]

Summary

The size of the vector is being increased by __n during the call to __move_range and not by 1.
This fixes a test failure in containers/sequences/vector/vector.modifiers/insert_iter_size_value.pass.cpp when using ASAN.

[kcc]

can you re-send the patch with more context?

[EricWF]

This should have more context unless phab does something funny.

[mclow.lists]

LGTM

include/vector

             if (__n > static_cast<size_type>(this->__end_ - __p))
             {
                 size_type __cx = __n - (this->__end_ - __p);
                 __construct_at_end(__cx, __x);
                 __n -= __cx;
             }
             if (__n > 0)
             {
-                __RAII_IncreaseAnnotator __annotator(*this);
+                __RAII_IncreaseAnnotator __annotator(*this, __n);
                 __move_range(__p, __old_last, __p + __old_n);
                 __annotator.__done();
                 const_pointer __xr = pointer_traits<const_pointer>::pointer_to(__x);
                 if (__p <= __xr && __xr < this->__end_)
                     __xr += __old_n;
                 _VSTD::fill_n(__p, __n, *__xr);
             }
         }