Currently, the DWARF reader has a separate pass to read type units --
create_all_type_units. While working on other patches, I discovered
that this caused DWARF 5 type units to be read twice, once by
create_all_comp_units and once by create_all_type_units.
There's no need any more (if there ever was) to treat type units
differently from CUs. So, this patch removes create_all_type_units
and unifies the code paths.
Note that the DWO code still has a second pass. I haven't looked into
this code yet; perhaps it can also be simplified.
Regression tested using the debug-types board file on x86-64 Fedora 32.
gdb/ChangeLog
2021-04-30 Tom Tromey <tom@tromey.com>