We used to store a full vector of "views" of the registered test infos,
so that it can be retrieved externally. However, the only user of that
interface left was `Session`, specifically `Session::applyFilenameAsTags`.

By moving the adding of the filename tags into the `ITestCaseRegistry`
interface, we avoid storing the vector and make the initial test registration
faster.

The new code is ugly and shows a design/layering issue, but no worse than
the previous approach did.

Preallocating to some reasonable and small number of tests avoids
much of the geometric-reallocation threashing at low sizes, without
taking up too much memory for tiny test binaries.

This fixes compilation issue with C++23 mode against libstdc++.

Closes #2852

Classes will automatically inherit the virtual-ness of their base
class destructors. If the base class already has a virtual
destructor and the derived class needs default destructor semantics
then the derived class can omit defining the destructor in favor of
the compiler automatically defining it.

This has an additional benefit of reenabling move semantics. The
presence of a user-specified destructor automatically disables move
operations.

Closes #2682

The license file was renamed with 6a502cc2f5fedd59b3495b58708f0d6d987ed9e1