revision-id: psergey@askmonty.org-20140204092710-2yt5ysa5ej3l2c03
MDEV-5606: range optimizer: "x < y" is sargable, while "y > x" is not
Port to mariadb-1.0 the following fix from mysql-5.6:
      
Revision ID: jorgen.loland@oracle.com-20120314131055-ml54x9deueqfsff4
BUG#13701206: WHERE A>=B DOES NOT GIVE SAME EXECUTION PLAN
              AS WHERE B<=A (RANGE OPTIMIZER)
       
that fix didn't have a public testcase, so I created one.