Auto merge of #3263 - str4d:ibd-upstream-changes, r=bitcartel

InitialBlockDownload upstream changes

Cherry-picked from the following upstream PRs:

- bitcoin/bitcoin#7208
- bitcoin/bitcoin#8007
- bitcoin/bitcoin#9053
  - Excluding second commit (requires bitcoin/bitcoin#8865)
- bitcoin/bitcoin#10388

src/chainparams.h

@@ -77,7 +77,6 @@ public:
     bool DefaultConsistencyChecks() const { return fDefaultConsistencyChecks; }
     /** Policy: Filter transactions that do not match well-defined patterns */
     bool RequireStandard() const { return fRequireStandard; }
-    int64_t MaxTipAge() const { return nMaxTipAge; }
     int64_t PruneAfterHeight() const { return nPruneAfterHeight; }
     unsigned int EquihashN() const { return nEquihashN; }
     unsigned int EquihashK() const { return nEquihashK; }
@@ -107,7 +106,6 @@ protected:
     //! Raw pub key bytes for the broadcast alert signing key.
     std::vector<unsigned char> vAlertPubKey;
     int nDefaultPort = 0;
-    long nMaxTipAge = 0;
     uint64_t nPruneAfterHeight = 0;
     unsigned int nEquihashN = 0;
     unsigned int nEquihashK = 0;