[vm] Fix HashBytes to work with unaligned inputs.

TEST=ubsan
Bug: https://github.com/dart-lang/sdk/issues/63452
Change-Id: I112b26c08b5ae186dc5264d99edbed9e6e60368d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/506660
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/vm/hash.h

@@ -6,6 +6,7 @@
 #define RUNTIME_VM_HASH_H_
 
 #include "platform/globals.h"
+#include "platform/unaligned.h"
 
 namespace dart {
 
@@ -41,7 +42,8 @@ inline uint32_t HashBytes(const void* bytes,
   uint32_t hash = len;
   const intptr_t chunks = len / kInt32Size;
   for (intptr_t i = 0; i < chunks; i++) {
-    hash = CombineHashes(hash, reinterpret_cast<const uint32_t*>(bytes)[i]);
+    hash = CombineHashes(
+        hash, LoadUnaligned(&(reinterpret_cast<const uint32_t*>(bytes)[i])));
   }
   for (intptr_t i = chunks * kInt32Size; i < len; i++) {
     hash = CombineHashes(hash, reinterpret_cast<const uint8_t*>(bytes)[i]);