When we have a artificial constructor DIE, we currently create from that a global function with the name of that class.
That ends up causing a bunch of funny errors such as "must use 'struct' tag to refer to type 'Foo' in this scope" when
doing Foo f. Also causes that constructing a class via Foo() actually just calls that global function.
The fix is that when we have an artificial method decl, we always treat it as handled even if we don't create a CXXMethodDecl
for it (which we never do for artificial methods at the moment).
Fixes rdar://55757491 and probably some other radars.