Fix MSVC "result of 32-bit shift implicitly converted to 64 bits" warning. NFC. (#161496)

Author: RKSimon

llvm/lib/CAS/OnDiskTrieRawHashMap.cpp

@@ -114,7 +114,7 @@ class SubtrieHandle {
   using SlotT = std::atomic<int64_t>;
 
   static int64_t getSlotsSize(uint32_t NumBits) {
-    return sizeof(int64_t) * (1u << NumBits);
+    return sizeof(int64_t) * (1ull << NumBits);
   }
 
   static int64_t getSize(uint32_t NumBits) {
@@ -191,7 +191,8 @@ class SubtrieHandle {
   MutableArrayRef<SlotT> Slots;
 
   static MutableArrayRef<SlotT> getSlots(Header &H) {
-    return MutableArrayRef(reinterpret_cast<SlotT *>(&H + 1), 1u << H.NumBits);
+    return MutableArrayRef(reinterpret_cast<SlotT *>(&H + 1),
+                           1ull << H.NumBits);
   }
 };