refactor: remove unused Hash function variants

The three object variant was removed in dash#3276 through the backport
of bitcoin#11385, leaving behind the four, five and six variant options.
They aren't used anywhere in the codebase and aren't present in Bitcoin
Core currently, and so, have been removed.

Author: kwvg

src/hash.h

@@ -106,60 +106,6 @@ inline uint256 Hash(const T1 p1begin, const T1 p1end,
     return result;
 }
 
-/** Compute the 256-bit hash of the concatenation of three objects. */
-template<typename T1, typename T2, typename T3, typename T4>
-inline uint256 Hash(const T1 p1begin, const T1 p1end,
-                    const T2 p2begin, const T2 p2end,
-                    const T3 p3begin, const T3 p3end,
-                    const T4 p4begin, const T4 p4end) {
-    static const unsigned char pblank[1] = {};
-    uint256 result;
-    CHash256().Write(p1begin == p1end ? pblank : (const unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]))
-              .Write(p2begin == p2end ? pblank : (const unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]))
-              .Write(p3begin == p3end ? pblank : (const unsigned char*)&p3begin[0], (p3end - p3begin) * sizeof(p3begin[0]))
-              .Write(p4begin == p4end ? pblank : (const unsigned char*)&p4begin[0], (p4end - p4begin) * sizeof(p4begin[0]))
-              .Finalize((unsigned char*)&result);
-    return result;
-}
-
-/** Compute the 256-bit hash of the concatenation of three objects. */
-template<typename T1, typename T2, typename T3, typename T4, typename T5>
-inline uint256 Hash(const T1 p1begin, const T1 p1end,
-                    const T2 p2begin, const T2 p2end,
-                    const T3 p3begin, const T3 p3end,
-                    const T4 p4begin, const T4 p4end,
-                    const T5 p5begin, const T5 p5end) {
-    static const unsigned char pblank[1] = {};
-    uint256 result;
-    CHash256().Write(p1begin == p1end ? pblank : (const unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]))
-              .Write(p2begin == p2end ? pblank : (const unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]))
-              .Write(p3begin == p3end ? pblank : (const unsigned char*)&p3begin[0], (p3end - p3begin) * sizeof(p3begin[0]))
-              .Write(p4begin == p4end ? pblank : (const unsigned char*)&p4begin[0], (p4end - p4begin) * sizeof(p4begin[0]))
-              .Write(p5begin == p5end ? pblank : (const unsigned char*)&p5begin[0], (p5end - p5begin) * sizeof(p5begin[0]))
-              .Finalize((unsigned char*)&result);
-    return result;
-}
-
-/** Compute the 256-bit hash of the concatenation of three objects. */
-template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>
-inline uint256 Hash(const T1 p1begin, const T1 p1end,
-                    const T2 p2begin, const T2 p2end,
-                    const T3 p3begin, const T3 p3end,
-                    const T4 p4begin, const T4 p4end,
-                    const T5 p5begin, const T5 p5end,
-                    const T6 p6begin, const T6 p6end) {
-    static const unsigned char pblank[1] = {};
-    uint256 result;
-    CHash256().Write(p1begin == p1end ? pblank : (const unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]))
-              .Write(p2begin == p2end ? pblank : (const unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]))
-              .Write(p3begin == p3end ? pblank : (const unsigned char*)&p3begin[0], (p3end - p3begin) * sizeof(p3begin[0]))
-              .Write(p4begin == p4end ? pblank : (const unsigned char*)&p4begin[0], (p4end - p4begin) * sizeof(p4begin[0]))
-              .Write(p5begin == p5end ? pblank : (const unsigned char*)&p5begin[0], (p5end - p5begin) * sizeof(p5begin[0]))
-              .Write(p6begin == p6end ? pblank : (const unsigned char*)&p6begin[0], (p6end - p6begin) * sizeof(p6begin[0]))
-              .Finalize((unsigned char*)&result);
-    return result;
-}
-
 /** Compute the 160-bit hash an object. */
 template<typename T1>
 inline uint160 Hash160(const T1 pbegin, const T1 pend)