Remove symbolic links (#3369)

* Validate symbolic links and add clear instructions for Windows devs

* copy files instead of sym links

* type changed

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Co-authored-by: Yi Zhang <you@example.com>

test/integration/assets/sprites/icon-text-fit-1x@2x.json

@@ -0,0 +1,26 @@
+{
+  "label": {
+    "x": 0,
+    "y": 0,
+    "width": 76,
+    "height": 38,
+    "pixelRatio": 1,
+    "sdf": false
+  },
+  "small-box": {
+    "x": 76,
+    "y": 0,
+    "width": 18,
+    "height": 10,
+    "pixelRatio": 1,
+    "sdf": false
+  },
+  "tall-box": {
+    "x": 76,
+    "y": 10,
+    "width": 18,
+    "height": 28,
+    "pixelRatio": 1,
+    "sdf": false
+  }
+}

test/integration/assets/sprites/icon-text-fit-2x.json

@@ -0,0 +1,26 @@
+{
+  "label": {
+    "x": 0,
+    "y": 0,
+    "width": 152,
+    "height": 76,
+    "pixelRatio": 2,
+    "sdf": false
+  },
+  "small-box": {
+    "x": 152,
+    "y": 0,
+    "width": 36,
+    "height": 20,
+    "pixelRatio": 2,
+    "sdf": false
+  },
+  "tall-box": {
+    "x": 152,
+    "y": 20,
+    "width": 36,
+    "height": 56,
+    "pixelRatio": 2,
+    "sdf": false
+  }
+}