windows: use 'str.replace()' instead of combination of split() and join() 'str.replace()' is twice (or more) as fast as combination of split() and join(). combination of split() and join() in current 'util.pconvert()' implementation comes only from historical reason when win32mbcs extension was introduced.

largefiles: reduce redundant splitstandin/standin combination assumptions: - 'lfutil.splitstandin(f)' strips 'f' of '.hglf/', if it can - 'lfile(f)' examines 'lfutil.standin(f) in manifest' - 'lfutil.standin(f)' adds '.hglf/' to 'f' and - 'f' should start with '.hglf/' there, because it is already examined by 'lfutil.isstandin(f)' then: lfile(lfutil.splitstandin(f)) => lfile(<f without '.hglf/'>) => lfutil.standin(<f without '.hglf/'>) in manifest => <<f without '.hglf/'> with '.hglf/'> in manifest => f in manifest

largefiles: reduce OR-ing of same conditions