First part (row0mysql.cc) fixes ins_node_set_new_row() usage workflow
as it is designed to operate on empty row (see row_get_prebuilt_insert_row()
for example).

Second part (row0ins.cc) fixes duplicate key error in FTS_DOC_ID_INDEX
since history rows must not generate entries in that index. We detect
FTS_DOC_ID_INDEX by a number of attributes and skip it if the row is
historical.

Misc fixes:

row_build_index_entry_low() does not accept non-NULL tuple
for FTS index (subject assertion fails), assertion (index->type !=
DICT_FTS) adds code understanding.

Now as historical_row is copied in row_update_vers_insert() there is
no need to copy the row twice: ROW_COPY_POINTERS is used to build
historical_row initially.

dbug_print_rec() debug functions.