Fix "result of 32-bit shift implicitly converted to 64 bits" MSVC warning. NFCI.

The shift of 1 by an amount that is never more than 31 means that the warning is a false positive but is safe and fixes Werror builds.
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 4c8e95e..5f6d8bf 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -9430,7 +9430,7 @@
     llvm::computeKnownBits(GV, Known, getDataLayout());
     unsigned AlignBits = Known.countMinTrailingZeros();
     if (AlignBits)
-      return commonAlignment(Align(1 << std::min(31U, AlignBits)), GVOffset);
+      return commonAlignment(Align(1ull << std::min(31U, AlignBits)), GVOffset);
   }
 
   // If this is a direct reference to a stack slot, use information about the