[sanitizer] Revert rL324263

[cryptoad]

Summary

The 32-bit division breaks SizeClassAllocator64PopulateFreeListOOM which uses
Primary that has a maximum size > 32-bit.

compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator_size_class_map.h

public:
 
   static uptr ClassID(uptr size) {
     if (UNLIKELY(size > kMaxSize))
       return 0;
     if (size <= kMidSize)
       return (size + kMinSize - 1) >> kMinSizeLog;
     uptr l = MostSignificantSetBitIndex(size);
     uptr hbits = (size >> (l - S)) & M;
-    uptr lbits = size & ((1U << (l - S)) - 1);
+    uptr lbits = size & ((1 << (l - S)) - 1);
     uptr l1 = l - kMidSizeLog;
     return kMidClass + (l1 << S) + hbits + (lbits > 0);
   }
 
   static uptr MaxCachedHint(uptr class_id) {
     // Estimate the result for kBatchClassID because this class does not know
     // the exact size of TransferBatch. We need to cache fewer batches than user
     // chunks, so this number can be small.
     if (UNLIKELY(class_id == kBatchClassID))
       return 16;
     if (UNLIKELY(class_id == 0))
       return 0;
-    const uptr n =
-        (1U << kMaxBytesCachedLog) / static_cast<u32>(Size(class_id));
+    uptr n = (1UL << kMaxBytesCachedLog) / Size(class_id);
     return Max<uptr>(1, Min(kMaxNumCachedHint, n));
   }
 
   static void Print() {
     uptr prev_s = 0;
     uptr total_cached = 0;
     for (uptr i = 0; i < kNumClasses; i++) {
       uptr s = Size(i);