Do not fill errors with thousands of errors

Instead of fill errors ansistring variable with thousands of errors, show only first errors. This improves speed when there are thousands of invalid operations!

src/core/UNode.pas

@@ -429,8 +429,10 @@ begin
              (FOperations.OperationsHashTree.CountOperationsBySameSignerWithoutFee(ActOp.SignerAccount)>=CT_MaxAccountOperationsPerBlockWithoutFee) then begin
             inc(nSpam);
             e := Format('Account %s zero fee operations per block limit:%d',[TAccountComp.AccountNumberToAccountTxtNumber(ActOp.SignerAccount),CT_MaxAccountOperationsPerBlockWithoutFee]);
-            if (errors<>'') then errors := errors+' ';
-            errors := errors+'Op '+IntToStr(j+1)+'/'+IntToStr(OperationsHashTree.OperationsCount)+':'+e;
+            if (nSpam<=5) then begin  // To Limit errors in a String... speed up
+              if (errors<>'') then errors := errors+' ';
+              errors := errors+'Op '+IntToStr(j+1)+'/'+IntToStr(OperationsHashTree.OperationsCount)+':'+e;
+            end;
             TLog.NewLog(ltdebug,Classname,Format('AddOperation spam %d/%d: %s  - Error:%s',
               [(j+1),OperationsHashTree.OperationsCount,ActOp.ToString,e]));
             if Assigned(OperationsResult) then begin
@@ -455,8 +457,10 @@ begin
               end;
             end else begin
               inc(nError);
-              if (errors<>'') then errors := errors+' ';
-              errors := errors+'Op '+IntToStr(j+1)+'/'+IntToStr(OperationsHashTree.OperationsCount)+':'+e;
+              if (nError<=5) then begin  // To Limit errors in a String... speed up
+                if (errors<>'') then errors := errors+' ';
+                errors := errors+'Op '+IntToStr(j+1)+'/'+IntToStr(OperationsHashTree.OperationsCount)+':'+e;
+              end;
               TLog.NewLog(ltdebug,Classname,Format('AddOperation invalid/duplicated %d/%d: %s  - Error:%s',
                 [(j+1),OperationsHashTree.OperationsCount,ActOp.ToString,e]));
               if Assigned(OperationsResult) then begin
@@ -485,8 +489,10 @@ begin
         end else begin
           inc(nRepeated);
           e := Format('AddOperation made before %d/%d: %s',[(j+1),OperationsHashTree.OperationsCount,ActOp.ToString]);
-          if (errors<>'') then errors := errors+' ';
-          errors := errors + e;
+          if (nRepeated<=5) then begin  // To Limit errors in a String... speed up
+            if (errors<>'') then errors := errors+' ';
+            errors := errors + e;
+          end;
           if Assigned(OperationsResult) then begin
             TPCOperation.OperationToOperationResume(0,ActOp,True,ActOp.SignerAccount,OPR);
             OPR.valid := false;