ET_HAS_EXCEPTIONS: require defined(_MSC_VER) to conclude _HAS_EXCEPTIONS implies exceptions are on (#11831)

This PR was created by the merge bot to help merge the original PR into
the main branch.
ghstack PR number: #11770 by
@swolchok
^ Please use this as the source of truth for the PR details, comments,
and reviews
ghstack PR base:
https://github.com/pytorch/executorch/tree/gh/swolchok/461/base
ghstack PR head:
https://github.com/pytorch/executorch/tree/gh/swolchok/461/head
Merge bot PR base: https://github.com/pytorch/executorch/tree/main
Merge bot PR head:
https://github.com/pytorch/executorch/tree/gh/swolchok/461/orig
@diff-train-skip-merge

Co-authored-by: Scott Wolchok <[email protected]>

Author: pytorchbot

runtime/platform/compiler.h

@@ -173,7 +173,7 @@ using ssize_t = ptrdiff_t;
 
 #ifdef __EXCEPTIONS
 #define ET_HAS_EXCEPTIONS 1
-#elif defined(_HAS_EXCEPTIONS) && _HAS_EXCEPTIONS
+#elif defined(_MSC_VER) && defined(_HAS_EXCEPTIONS) && _HAS_EXCEPTIONS
 #define ET_HAS_EXCEPTIONS 1
 #else
 #define ET_HAS_EXCEPTIONS 0