Got rid of log_01[], because we don't really need it. Division and log_10[] can always be used instead, which is also a more precise way.

This is for bug #28121.


include/m_string.h:
  Got rid of log_01[], because we don't really need it.
sql/item_cmpfunc.cc:
  Got rid of log_01[], because we don't really need it.
strings/strtod.c:
  Got rid of log_01[], because we don't really need it.