This change introduces an umbrella header for prefetch_<os>_<cpu>.inline.hpp
files: runtime/prefetch.inline.hpp. This follows the scheme applied to
atomic.inline.hpp.

Further this change adds includes of prefetch.inline.hpp in all .cpp
and .inline.hpp files where a method of Prefetch declared 'inline' is
called.

Finally it moves macros calling inline methods of Prefetch from
space.hpp to the corresponding .inline.hpp file and adds the necessary
includes in files using the moved macros.