Optimizer Trace: Q1 2026 Dev fixes

Hook records_in_range call

in opt_range.cc in ror_scan_add, there is a handler->records_in_range() call.
We need to hook it: save and return back its value.

Note that ha_something::multi_range_read_info_const() as well as handler::multi_range_read_info_const() also make calls to handler->records_in_range() and we do NOT need to intercept them.

Example query that uses index_merge/intersection and depends on records_in_range() value:

INDEX i1(a, b)

INDEX i2(a, c) 

select * from t1 where a=1 and b=1 and c=1;

or try INDEX(c,a), INDEX(b, a).