[libc++][test] Partially revert msvc_stdlib_force_include.h _Pragma change

... keep the warning suppression, but revert the `__pragma` to `_Pragma` change because `_Pragma` interacts badly with `/Zc:preprocessor`.

diff --git a/libcxx/test/support/msvc_stdlib_force_include.h b/libcxx/test/support/msvc_stdlib_force_include.h
index 77d7222..cf8696a 100644 (file)
--- a/libcxx/test/support/msvc_stdlib_force_include.h
+++ b/libcxx/test/support/msvc_stdlib_force_include.h
@@ -100,11 +100,11 @@ const AssertionDialogAvoider assertion_dialog_avoider{};
     _Pragma("GCC diagnostic pop")
 #else // ^^^ clang / MSVC vvv
 #define _LIBCPP_SUPPRESS_DEPRECATED_PUSH \
-    _Pragma("warning(push)") \
-    _Pragma("warning(disable : 4996)") \
-    _Pragma("warning(disable : 5215)")
+    __pragma(warning(push)) \
+    __pragma(warning(disable : 4996)) \
+    __pragma(warning(disable : 5215))
 #define _LIBCPP_SUPPRESS_DEPRECATED_POP \
-    _Pragma("warning(pop)")
+    __pragma(warning(pop))
 #endif // __clang__
 
 #endif // SUPPORT_MSVC_STDLIB_FORCE_INCLUDE_H