The 'single point' event was forgotten in the relation's calculation

per-file comments:
  mysql-test/r/gis-precise.result
fix for bug 857051 ST_EQUALS returns TRUE on two nonidentical MULTIPOINTs
        test result updated.
  mysql-test/t/gis-precise.test
fix for bug 857051 ST_EQUALS returns TRUE on two nonidentical MULTIPOINTs
        test case added.
  sql/gcalc_tools.cc
fix for bug 857051 ST_EQUALS returns TRUE on two nonidentical MULTIPOINTs
        scev_single_point is properly handled.