Do not use std::iterator that is deprecated in c++17.

Author: bshastry

libevmasm/BlockDeduplicator.h

@@ -64,9 +64,14 @@ class BlockDeduplicator
 	/// Iterator that skips tags and skips to the end if (all branches of) the control
 	/// flow does not continue to the next instruction.
 	/// If the arguments are supplied to the constructor, replaces items on the fly.
-	struct BlockIterator: std::iterator<std::forward_iterator_tag, AssemblyItem const>
+	struct BlockIterator
 	{
 	public:
+		using iterator_category = std::forward_iterator_tag;
+		using value_type = AssemblyItem const;
+		using difference_type = long;
+		using pointer = AssemblyItem const*;
+		using reference = AssemblyItem const&;
 		BlockIterator(
 			AssemblyItems::const_iterator _it,
 			AssemblyItems::const_iterator _end,