revamp test case for high precision

Author: monfera

test/image/baselines/gl2d_date_axes.png

@@ -2,16 +2,40 @@
     "data": [
         {
             "x": [
-                "2013-10-04 22:23:00",
-                "2013-11-04 22:23:00",
-                "2013-12-04 22:23:00"
+                "1970-10-25 22:23:00",
+                "1970-10-25 22:23:00.001",
+                "1970-10-25 22:23:00.002",
+                "1970-10-25 22:23:00.003",
+                "1970-10-25 22:23:00.004",
+                "2016-10-25 22:23:00",
+                "2016-10-25 22:23:00.001",
+                "2016-10-25 22:23:00.002",
+                "2016-10-25 22:23:00.003",
+                "2016-10-25 22:23:00.004"
             ],
             "y": [
+                0,
                 1,
+                2,
                 3,
-                6
+                4,
+                5,
+                6,
+                7,
+                8,
+                9
             ],
-            "type": "scattergl"
+            "type": "scattergl",
+            "mode": "markers"
         }
-    ]
+    ],
+    "layout": {
+        "xaxis": {
+            "range": [
+                1477426980000,
+                1477426980004
+            ],
+            "autorange": true
+        }
+    }
 }