Remove workarounds for [D]CHECK()s in constexpr functions.

We're now using C++14, so we can use [D]CHECK()s directly
in constexpr functions. Remove the C++11 workaround macros
([D]CHECK_CONSTEXPR) and C++ version checks. Also remove the
'static' qualifier from inline functions in affected files.

Test: m test-art-host
Change-Id: I0f962ad75e4efe9b65325d022cd272b229574222