[IR] Bump AttributeBitSet width to 16 bytes (#106138)

Author: yuxuanchen1997

llvm/lib/IR/AttributeImpl.h

@@ -275,7 +275,7 @@ class ConstantRangeListAttributeImpl final
 
 class AttributeBitSet {
   /// Bitset with a bit for each available attribute Attribute::AttrKind.
-  uint8_t AvailableAttrs[12] = {};
+  uint8_t AvailableAttrs[16] = {};
   static_assert(Attribute::EndAttrKinds <= sizeof(AvailableAttrs) * CHAR_BIT,
                 "Too many attributes");