Check for number of line strings in the incoming polygon data (wkb) and
for number of points in the incoming linestring wkb.



mysql-test/r/gis.result:
  Fix for bug #51875: crash when loading data into geometry function polyfromwkb
    - test result.
mysql-test/t/gis.test:
  Fix for bug #51875: crash when loading data into geometry function polyfromwkb
    - test case.
sql/spatial.cc:
  Fix for bug #51875: crash when loading data into geometry function polyfromwkb
    - creating a polygon from wkb check for number of line strings,
    - creating a linestring from wkb check for number of line points.