skip Axes.makeClipPaths under hasOnlyLargeSploms regime

- these clip paths are only used for shapes and layout images,
  which make hasOnlyLargeSploms false, so we don't need them.
- this can trim ~50ms on first render at 50 splom dimensions.

Author: etpinard

src/plots/cartesian/axes.js

@@ -1456,6 +1456,10 @@ axes.findSubplotsWithAxis = function(subplots, ax) {
 // makeClipPaths: prepare clipPaths for all single axes and all possible xy pairings
 axes.makeClipPaths = function(gd) {
     var fullLayout = gd._fullLayout;
+
+    // for more info: https://github.com/plotly/plotly.js/issues/2595
+    if(fullLayout._hasOnlyLargeSploms) return;
+
     var fullWidth = {_offset: 0, _length: fullLayout.width, _id: ''};
     var fullHeight = {_offset: 0, _length: fullLayout.height, _id: ''};
     var xaList = axes.list(gd, 'x', true);