test: add sample for unquoted attributes

packages/svelte/tests/parser-legacy/samples/attribute-unquoted/input.svelte

@@ -1 +1,2 @@
-<div class=foo></div>
+<div class=foo></div>
+<a href=/>home</a>

packages/svelte/tests/parser-legacy/samples/attribute-unquoted/output.json

@@ -2,7 +2,7 @@
 	"html": {
 		"type": "Fragment",
 		"start": 0,
-		"end": 21,
+		"end": 40,
 		"children": [
 			{
 				"type": "Element",
@@ -27,6 +27,45 @@
 					}
 				],
 				"children": []
+			},
+			{
+				"type": "Text",
+				"start": 21,
+				"end": 22,
+				"raw": "\n",
+				"data": "\n"
+			},
+			{
+				"type": "Element",
+				"start": 22,
+				"end": 40,
+				"name": "a",
+				"attributes": [
+					{
+						"type": "Attribute",
+						"start": 25,
+						"end": 31,
+						"name": "href",
+						"value": [
+							{
+								"start": 30,
+								"end": 31,
+								"type": "Text",
+								"raw": "/",
+								"data": "/"
+							}
+						]
+					}
+				],
+				"children": [
+					{
+						"type": "Text",
+						"start": 32,
+						"end": 36,
+						"raw": "home",
+						"data": "home"
+					}
+				]
 			}
 		]
 	}