Add image test for #3770

Author: daveholladay

test/image/baselines/axes_linked_date_autorange.png

@@ -0,0 +1,50 @@
+{
+  "data": [
+    {
+      "x": [
+        "2019-04-01", 
+        "2019-04-02", 
+        "2019-04-03"
+      ], 
+      "y": [
+        1, 
+        2, 
+        3
+      ],
+      "type": "scatter" 
+    }, 
+    {
+      "x": [
+        "2019-04-06", 
+        "2019-04-07", 
+        "2019-04-08"
+      ], 
+      "y": [
+        4, 
+        5, 
+        6
+      ],
+      "xaxis": "x2", 
+      "type": "scatter"
+    }
+  ], 
+  "layout": {
+    "xaxis": {
+      "autorange": true, 
+      "domain": [
+        0, 
+        0.45
+      ], 
+      "type": "date"
+    }, 
+    "xaxis2": {
+      "autorange": true, 
+      "domain": [
+        0.55, 
+        1.0
+      ], 
+      "matches": "x", 
+      "type": "date"
+    }
+  }
+}