[material][3pimmiscible] Clang does not compile with DUNE_THROW in constexpr function
!1726 (merged) introduced a DUNE_THROW as default case for a switch in, e.g.,
static constexpr bool isGas(int phaseIdx)
because the compiler would rise a warning otherwise. However, clang does not allow Dune exceptions in constexpr functions.
How should we handle this? Just return
false per default, omitting the DUNE_THROW?