[Maria-developers] MDEV-4511 Assertion `scale <= precision' fails on GROUP BY TIMEDIFF with incorrect types

Hello Sergei, Please review a new version of the patch for MDEV-4511, it also fixes more crashing problems found, as well as non-crashing problems reported in MDEV-6302 I removed find_num_type() and fix_num_length_and_dec() which were hard to track, and for some Items these methods were erroneously called twice. fix_num_length_and_dec() now only exists as a non-virtual method in Item_sum and Item_udf_func. The patch is for 5.3, but it is still valid for 10.0, as we still have temporal functions with NOT_FIXED_DEC in 10.0. Thanks.