libs/common: remove deprecated PanicXXX functions (#3595)

* Remove deprecated PanicXXX functions from codebase

As per discussion over
[here](https://github.com/tendermint/tendermint/pull/3456#discussion_r278423492),
we need to remove these `PanicXXX` functions and eliminate our
dependence on them. In this PR, each and every `PanicXXX` function call
is replaced with a simple `panic` call.

* add a changelog entry

consensus/types/height_vote_set.go

@@ -6,7 +6,6 @@ import (
 	"strings"
 	"sync"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/types"
 )
@@ -83,7 +82,7 @@ func (hvs *HeightVoteSet) SetRound(round int) {
 	hvs.mtx.Lock()
 	defer hvs.mtx.Unlock()
 	if hvs.round != 0 && (round < hvs.round+1) {
-		cmn.PanicSanity("SetRound() must increment hvs.round")
+		panic("SetRound() must increment hvs.round")
 	}
 	for r := hvs.round + 1; r <= round; r++ {
 		if _, ok := hvs.roundVoteSets[r]; ok {
@@ -96,7 +95,7 @@ func (hvs *HeightVoteSet) SetRound(round int) {
 
 func (hvs *HeightVoteSet) addRound(round int) {
 	if _, ok := hvs.roundVoteSets[round]; ok {
-		cmn.PanicSanity("addRound() for an existing round")
+		panic("addRound() for an existing round")
 	}
 	// log.Debug("addRound(round)", "round", round)
 	prevotes := types.NewVoteSet(hvs.chainID, hvs.height, round, types.PrevoteType, hvs.valSet)
@@ -169,8 +168,7 @@ func (hvs *HeightVoteSet) getVoteSet(round int, type_ types.SignedMsgType) *type
 	case types.PrecommitType:
 		return rvs.Precommits
 	default:
-		cmn.PanicSanity(fmt.Sprintf("Unexpected vote type %X", type_))
-		return nil
+		panic(fmt.Sprintf("Unexpected vote type %X", type_))
 	}
 }