SmartPtr: Remove obsolete MSVC version checks.
Remove obsolete MSVC check from pragma guard

 git grep -h -B1 "^#\s*pragma once" | grep -v pragma | sort | uniq

is now clean.
Revert MSC_VER changes.
Remove #pragma intrinsic( _mm_pause ); not needed, not supported on Intel. Refs #6646, #7318.
Remove use of obsolete BOOST_NO_TEMPLATED_STREAMS macro.

It was only defined for no-longer-supported-gcc.
SmartPointer: Remove obsolete GCC version checks.