2020-04-27 Rec v21r9

This version uses Lbcom v20r9, LHCb v42r12, Gaudi v28r2p1 and LCG_88 with ROOT 6.08.06.

This version is released on 2017-patches branch.

Built relative to Rec v21r8, with the following changes:

Code cleanups and changes to tests modernisation cleanup testing

• Tracking | Remove upgrade tracking, !1954, !1921 (@cattanem)
• Build | Remove Win32 dead code and build directives, !2014 (@cattanem)
• Build | Remove unnecessary COOL dependency, !1908 (@cattanem)
• CaloTools - replace std::auto_ptr with std::unique_ptr, !1889 (@cattanem)
• Complete the removal of upgrade options from the Reco configuration, !1868 (@cattanem)
• Remove PrLongLivedTracking and PrDebugUTTruthTool, only used for Upgrade, !1866 (@cattanem)