gdb/dwarf: set is_debug_types in signatured_type constructor

This makes it more obvious that all created signatured_type objects have
this flag set.

Also, remove an unnecessary assignment in create_cus_hash_table: when
constructing the dwarf2_per_cu_data object, is_debug_types is already
initialized to 0/false.

Change-Id: I6d28b17ac77edc040172254f6970d05ebc4a47f4
Approved-By: Tom Tromey <tom@tromey.com>
2 files changed