Improve vec::copy mem stat annotations

[Jan Hubicka]

Hi,
this patch annotates vec::copy so it shows better in stats.  I still do
not see how auto vecs gets miscounted.

Bootstrapped/regtested x86_64-linux, comitted.

Honza

        * vec.h (vec<T, va_heap, vl_ptr>::copy): Pass mem stat info.
diff --git a/gcc/vec.h b/gcc/vec.h
index 3ad26972a62..14d77e87342 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -1731,7 +1731,7 @@ vec<T, va_heap, vl_ptr>::copy (ALONE_MEM_STAT_DECL) const
 {
   vec<T, va_heap, vl_ptr> new_vec = vNULL;
   if (length ())
-    new_vec.m_vec = m_vec->copy ();
+    new_vec.m_vec = m_vec->copy (ALONE_PASS_MEM_STAT);
   return new_vec;
 }