Cleanup include directives for precompiled.hpp

The precompiled header file is:

src/hotspot/share/precompiled/precompiled.hpp

The normal way to include precompiled headers is to just have:

#include "precompiled.hpp"

as the first directive in a file. This works because the makefiles set:

 -I$(TOPDIR)/src/hotspot/share/precompiled

 Some files instead have:

#include "precompiled/precompiled.hpp"

./os/bsd/semaphore_bsd.cpp
./os/linux/waitBarrier_linux.cpp
./os/posix/semaphore_posix.cpp
./os/posix/signals_posix.cpp

This should be trivially cleaned up.