Basic: add explicit template parameters for disambiguation

When building with MSVC, this would fail to compile due to the `buffer`
type (`uint8_t [8]`) being treated as `unsigned char *`, which is
expecting to be SFINAE'd to fail find an overload for the hash
combination.

Author: compnerd

include/swift/Basic/Fingerprint.h

@@ -123,9 +123,9 @@ template <> struct StableHasher::Combiner<Fingerprint> {
     // raw bytes from the core by hand.
     uint8_t buffer[8];
     memcpy(buffer, &Val.core.first, sizeof(buffer));
-    hasher.combine(buffer);
+    hasher.combine<sizeof(buffer)>(buffer);
     memcpy(buffer, &Val.core.second, sizeof(buffer));
-    hasher.combine(buffer);
+    hasher.combine<sizeof(buffer)>(buffer);
   }
 };