tdf#170595 we can reduce re-alloc a little here

by sizing the vector up front

Change-Id: I69db8759c329525e25b05d13abd6c041b4b44965
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/199265
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

sw/source/core/doc/DocumentContentOperationsManager.cxx

@@ -4151,6 +4151,7 @@ void DocumentContentOperationsManager::CopyFlyInFlyImpl(
     // They are stored as matching the originals, so that we will be later
     // able to build the chains accordingly.
     std::vector< SwFrameFormat* > aVecSwFrameFormat;
+    aVecSwFrameFormat.reserve(aSet.size());
     std::set< ZSortFly >::const_iterator it=aSet.begin();
 
     while (it != aSet.end())