Upgrade coreclr c++ standard to c++17

[max-charlamb]

While working on the cDAC's datadescriptor infrastructure, several issues have come up that would be solved by moving coreclr to target c++17 instead of c++11 today. Most of these relate to constexpr and various relaxations in c++14 and c++17.

#118050 has faced several issues relating to getting the address of a type wrapped by the VOLATILE(T) macro as a constexpr. This is somewhat challenging because VOLATILE(T) sometimes is the volatile keyword and others a Volatile<T> wrapper class. The wrapper class overrides the built-in address-of operator &. This can be solved two different ways with features available in c++17:

• std::addressof allows getting the address of an object which overrides the & operator as a constexpr.
• Allowing non-const constexpr member functions. This would allow the Volatile<T> class to override the & operator and provide its address at compile time.

Other benefits

• inline constexpr variables Remove SELECTANY usage #39532 (comment)

[MihuBot]

Possible related and/or duplicate issues:

• Proposal: Upgrade C++ compiler feature level to C++ 17 #112419