MSVC and CoreChecker warning suppression for tests to CMake

Suppress CppCoreCheck warnings on GTest macros.
Suppress CppCoreCheck advice to use the GSL

tests/notnull_tests.cpp

@@ -14,15 +14,6 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-
-// Fix VS2015 build breaks in Release
-#pragma warning(disable : 4702) // unreachable code
-#endif
-
 #include <gtest/gtest.h>
 
 #include <gsl/pointers> // for not_null, operator<, operator<=, operator>