Merge #8173: Use SipHash for node eviction (cont'd)

eebc232 test: Add more test vectors for siphash (Wladimir J. van der Laan)
8884830 Use C++11 thread-safe static initializers (Pieter Wuille)
c31b24f Use 64-bit SipHash of netgroups in eviction (Pieter Wuille)
9bf156b Support SipHash with arbitrary byte writes (Pieter Wuille)
053930f Avoid recalculating vchKeyedNetGroup in eviction logic. (Patrick Strateman)

src/main.cpp

@@ -4783,11 +4783,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     LOCK(cs_vNodes);
                     // Use deterministic randomness to send to the same nodes for 24 hours
                     // at a time so the addrKnowns of the chosen nodes prevent repeats
-                    static uint64_t salt0 = 0, salt1 = 0;
-                    while (salt0 == 0 && salt1 == 0) {
-                        GetRandBytes((unsigned char*)&salt0, sizeof(salt0));
-                        GetRandBytes((unsigned char*)&salt1, sizeof(salt1));
-                    }
+                    static const uint64_t salt0 = GetRand(std::numeric_limits<uint64_t>::max());
+                    static const uint64_t salt1 = GetRand(std::numeric_limits<uint64_t>::max());
                     uint64_t hashAddr = addr.GetHash();
                     multimap<uint64_t, CNode*> mapMix;
                     const CSipHasher hasher = CSipHasher(salt0, salt1).Write(hashAddr << 32).Write((GetTime() + hashAddr) / (24*60*60));