Line autointersection point was treated as if it doesn't belong to the line.
        It's in some way logical, but seems to confuse people. Fixed.

per_file_comments:
  mysql-test/r/gis-precise.result
bug 857087 Wrong result with ST_INTERSECTS and LINESTRINGs
        test result updated.
  mysql-test/t/gis-precise.test
bug 857087 Wrong result with ST_INTERSECTS and LINESTRINGs
        test case added.
  sql/gcalc_tools.cc
bug 857087 Wrong result with ST_INTERSECTS and LINESTRINGs
        Point of line autointersection handled as it belongs to the line.
  sql/gcalc_tools.h
bug 857087 Wrong result with ST_INTERSECTS and LINESTRINGs
        Gcalc_function::set_i_state() added