PR19601: std::remove_if does not really remove the elements.

It moves them at the end of the range instead, so an extra erase is needed.

It is strange that this code works without the erase. On the other hand, removing the remove_if will make fail some tests.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@207696 91177308-0d34-0410-b5e6-96231b3b80d8