Assert fails due to overflow which happens in
Item_func_int_val::fix_num_length_and_dec() as
geometry functions have max_length value equal to
max_field_size(4294967295U). The fix is to skip
max_length calculation for some boundary cases.


mysql-test/r/func_math.result:
  test case
mysql-test/t/func_math.test:
  test case
sql/item_func.cc:
  skip max_length calculation
  if argument max_length is near max_field_size.