Remove remaining Python2 backwards-compatibilty code.

See merge request gaudi/Gaudi!1503

Make the printout of `set` properties reproducible. For GaudiConfig2,
this is done via the property `repr` itself. For the legacy
Configurables, only in the `str` printout.

See merge request gaudi/Gaudi!1525

See merge request gaudi/Gaudi!1524

See merge request gaudi/Gaudi!1518

Closes #282

See merge request gaudi/Gaudi!1522

To support `Gaudi::Property<DataOjbIDColl>` we need to allow implicit
conversion from `tuple`.

Allow only `list` types to be assigned to `list` properties and extend
test coverage. This brings GaudiConfig2 in line with the legacy
configurables. I.e. the following now fails:
```
  MyAlg.MyVecOfStrings = "abc"
```

See merge request gaudi/Gaudi!1519

See merge request gaudi/Gaudi!1513

See merge request gaudi/Gaudi!1516

See merge request gaudi/Gaudi!1515

See merge request gaudi/Gaudi!1512

For backwards compatibility, allow the following code:
```
   alg.MySetProperty = [1, 2, 3]
```

Change the Python type of `std::unordered_set` properties from `list` to `set`.
Parsers only required minor updates and special treatment of the empty
set, which can only be represented as `set()` in Python (`{}` is
reserved for dictionaries).

This will certainly break client code, i.e.
```
   MyAlg.ExtraInputs += ['foo']
```
will have to be updated to
```
  MyAlg.ExtraInputs.add('foo')
```

For the moment only `std::unordered_set` is mapped to a Python `set`.
Regular `std::set` remains as Python `list` to maintain insertion order.

See merge request gaudi/Gaudi!1517

Fix the cleanup function and extend the test to `dict` and `list`
proprties. Also migrate to `pytest` fixtures and exception handling.

See merge request gaudi/Gaudi!1514

    
Work around libstdc++ bug in the std::string range ctor that can trigger
an abort in ubsan.  See ATEAM-937 and
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109703

- remove duplicated constructor
- add const
- add final
- do not inherit from SmartRef just to create dictionary instances
- prefer nullptr over 0

See merge request gaudi/Gaudi!1506

See merge request gaudi/Gaudi!1511

scott snyder authored 1 year ago and Marco Clemencic committed 1 year ago

GaudiHandleBase has a virtual destructor which is declared with `=default'.
However. in C++20 mode, clang will then try to instiantiate all the virtual
functions for classes derived from this whenever the declarations
for those classes are seen.  The upshot is that then using Gaudi handles
with forward-declared classes doesn't work (even if the handle is only
declared in the header but not used in any way).

It turns out that we can avoid this behavior by changing the declaration
of the base class destructor to say `{}' instead of `=default'.
(This is perhaps a clang bug, but the standard is not very clear
on exactly when virtual members of the templated class are required
to be or not to be implicitly instantiated.)

See also ATLINFR-5113.

See merge request !1510