rpcserver: Calc verify progress based on best hdr.

This modifies the RPC server getblockchaininfo to base the verification
progress calculation on the best header now that all headers are
determined prior to downloading and verifying blocks.

internal/rpcserver/rpcserver.go

@@ -2035,10 +2035,10 @@ func handleGetBlockchainInfo(_ context.Context, s *Server, cmd interface{}) (int
 	}
 
 	// Estimate the verification progress of the node.
-	syncHeight := s.cfg.SyncMgr.SyncHeight()
 	var verifyProgress float64
-	if syncHeight > 0 {
-		verifyProgress = math.Min(float64(best.Height)/float64(syncHeight), 1.0)
+	if bestHeaderHeight > 0 {
+		progress := float64(best.Height) / float64(bestHeaderHeight)
+		verifyProgress = math.Min(progress, 1.0)
 	}
 
 	// Fetch the maximum allowed block size for all blocks other than the
@@ -2101,7 +2101,7 @@ func handleGetBlockchainInfo(_ context.Context, s *Server, cmd interface{}) (int
 		Chain:                params.Name,
 		Blocks:               best.Height,
 		Headers:              bestHeaderHeight,
-		SyncHeight:           syncHeight,
+		SyncHeight:           s.cfg.SyncMgr.SyncHeight(),
 		ChainWork:            fmt.Sprintf("%064x", chainWork),
 		InitialBlockDownload: !chain.IsCurrent(),
 		VerificationProgress: verifyProgress,

internal/rpcserver/rpcserverhandlers_test.go

@@ -3519,7 +3519,7 @@ func TestHandleGetBlockchainInfo(t *testing.T) {
 			SyncHeight:           int64(463074),
 			ChainWork:            "000000000000000000000000000000000000000000115d2833849090b0026506",
 			InitialBlockDownload: true,
-			VerificationProgress: float64(0.9999978405179302),
+			VerificationProgress: float64(1),
 			BestBlockHash:        "00000000000000001e6ec1501c858506de1de4703d1be8bab4061126e8f61480",
 			Difficulty:           uint32(404696953),
 			DifficultyRatio:      float64(35256672611.3862),