...by structurally comparing complex constexpr exprs that use template functions
that happen to not have been instantiated, so Expr::EvaluateAsRValue et al would
fail.  (Which happened with SFX_PRINTER_ALL in SfxViewShell::SetPrinter,
include/sfx2/viewsh.hxx.)

Now all of the LO code base should compile without causing
checkIdenticalDefaultArguments to return Maybe.

Change-Id: I2b103418c2c68f6d2242535c9cca3222a2508778
Reviewed-on: https://gerrit.libreoffice.org/44773Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>