Revert "[ADT] Fix SmallVector unused template instantiation on 32-bit systems."

This reverts commit 25e2e92.

Buildbot failure.

Author: browneee

llvm/lib/Support/SmallVector.cpp

@@ -78,18 +78,4 @@ void SmallVectorBase<Size_T>::grow_pod(void *FirstEl, size_t MinCapacity,
 }
 
 template class llvm::SmallVectorBase<uint32_t>;
-
-// Disable the uint64_t instantiation for 32-bit builds.
-// Both uint32_t and uint64_t instantations are needed for 64-bit builds.
-// This instantiation will never be used in 32-bit builds, and will cause
-// warnings when sizeof(Size_T) > sizeof(size_t).
-#if SIZE_MAX > UINT32_MAX
 template class llvm::SmallVectorBase<uint64_t>;
-
-// Assertions to ensure this #if stays in sync with SmallVectorSizeType.
-static_assert(sizeof(SmallVectorSizeType<char>) == sizeof(uint64_t),
-              "Expected SmallVectorBase<uint64_t> variant to be in use.");
-#else
-static_assert(sizeof(SmallVectorSizeType<char>) == sizeof(uint32_t),
-              "Expected SmallVectorBase<uint32_t> variant to be in use.");
-#endif