[libc++][test] Update _LIBCPP_SUPPRESS_DEPRECATED_(PUSH|POP)

... in `msvc_stdlib_force_include.h` to also ignore new MSVC warning C5215 "'%s' a function parameter with volatile qualified type is deprecated in C++20". Since we're touching it, also update from non-standard `__pragma(meow)` to standard `_Pragma("meow")`.