Fix MSVC compilation.

- Fix a struct vs. class in forward declaration of std::hash
 - Fix an unsigned vs. signed compare in BitSetIterator
 - Fix the assumption that std::array::[const_]iterator is a pointer.
 - Fix for reinterpret_cast from uint64_t to uint64_t not being allowed
   for vulkan_platform.h
 - Fix for a 32bit shift being expanded to 64bit.

Bug: None
Change-Id: I5f2bf8745aa1ef1eba9916fcf6ff7801b48f61cf
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/24501
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>

src/common/HashUtils.h

@@ -90,7 +90,7 @@ size_t Hash(const std::bitset<N>& value) {
 
 namespace std {
     template <typename Index, size_t N>
-    class hash<ityp::bitset<Index, N>> {
+    struct hash<ityp::bitset<Index, N>> {
       public:
         size_t operator()(const ityp::bitset<Index, N>& value) const {
             return Hash(static_cast<const std::bitset<N>&>(value));