[gdb/symtab] Detect overlapping ranges in create_addrmap_from_gdb_index

In create_addrmap_from_gdb_index, use the return value of
addrmap_mutable::insert_empty to detect overlapping ranges.

Tested on x86_64-linux.

Approved-By: Simon Marchi <simon.marchi@efficios.com>
1 file changed