Remove obsolete condition checks in ConnectBlock

[denravonska]

ConnectBlock has a couple of checks which were added during a transition phase. These conditions can no longer evaluate to true.

Gridcoin-Research/src/main.cpp

Line 3431 in bea0b4b

if (IsResearcher(bb.cpid) && IsLockTimeWithinMinutes(GetBlockTime(), GetAdjustedTime(), 15) && !IsResearchAgeEnabled(pindex->nHeight))

Can no longer happen due to grandfather being beyond the research age start.

Gridcoin-Research/src/main.cpp

Line 3225 in bea0b4b

if (IsProofOfWork() && pindex->nHeight > nGrandfather)

PoW blocks stopped at block 2050. Further PoW blocks are rejected in AcceptBlock.

[denravonska]

Same issues as #1174.

[jamescowens]

Done by #1572.