Define the VPX_NO_RETURN macro for MSVC

Define the VPX_NO_RETURN macro for MSVC

Define VPX_NO_RETURN as __declspec(noreturn) for MSVC. See
https://docs.microsoft.com/en-us/cpp/cpp/noreturn?view=msvc-160

This requires moving VPX_NO_RETURN before function declarations because
__declspec(noreturn) must be placed there. Fortunately GCC's
__attribute__((noreturn)) can be placed either before or after function
declarations.

Change-Id: Id9bb0077e2a4f16ec2ca9c913dd93673a0e385cf