fix %H maskBreaks for values greater but on the same hour

... as the lower break bound

Author: etpinard

src/plots/cartesian/set_convert.js

@@ -645,7 +645,12 @@ module.exports = function setConvert(ax, fullLayout) {
                             bnds = Lib.simpleMap(brk.bounds, cleanNumber);
                             b0 = bnds[0];
                             b1 = bnds[1];
-                            vb = (new Date(v)).getUTCHours();
+                            var vDate = new Date(v);
+                            vb = vDate.getUTCHours() + (
+                                vDate.getUTCMinutes() * ONEMIN +
+                                vDate.getUTCSeconds() * ONESEC +
+                                vDate.getUTCMilliseconds()
+                            ) / ONEDAY;
                             if(bnds[0] > bnds[1]) doesCrossPeriod = true;
                             break;
                         case '':

test/jasmine/tests/axes_test.js

@@ -4195,6 +4195,35 @@ describe('Test axes', function() {
                 ]);
             });
 
+            it('should discard coords within break bounds - date %H / high precision case', function() {
+                _calc({
+                    x: [
+                        '2020-01-03 17:00',
+                        '2020-01-03 17:15',
+                        '2020-01-03 17:30',
+                        '2020-01-06 7:45',
+                        '2020-01-06 8:00',
+                        '2020-01-06 8:15',
+                        '2020-01-06 8:30'
+                    ]
+                }, {
+                    xaxis: {
+                        breaks: [
+                            {pattern: '%H', bounds: [17, 8]}
+                        ]
+                    }
+                });
+                _assert('with dflt operation', [
+                    Lib.dateTime2ms('2020-01-03 17:00'),
+                    BADNUM,
+                    BADNUM,
+                    BADNUM,
+                    Lib.dateTime2ms('2020-01-06 8:00'),
+                    Lib.dateTime2ms('2020-01-06 8:15'),
+                    Lib.dateTime2ms('2020-01-06 8:30')
+                ]);
+            });
+
             it('should discard coords within [values[i], values[i] + dvalue] bounds', function() {
                 var x = [
                     // Thursday