fix(chrome): emit data-testid so both resolvers name the same element

The V8 host names a web target by data-testid and TapSelector translates that
selector into a CSS attribute match, but the dump carried no such attribute
and no alias could supply one, since an alias only redirects to a key that
already holds the value. tree.Find was therefore always nil for exactly the
selectors examples/folio-web tags with.

Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX

internal/driver/chrome/testdata/selector-parity.html

@@ -5,10 +5,10 @@
     <title id="page-title">selector parity</title>
   </head>
   <body id="page-body">
-    <div id="summary_card" aria-label="summary_card, 3 customers">summary</div>
+    <div id="summary_card" data-testid="summary" aria-label="summary_card, 3 customers">summary</div>
     <div id="customer_list" aria-label="customer_list">
-      <div id="customer_row_a1" aria-label="customer_row_a1, Alice">Alice</div>
-      <div id="customer_row_b2" aria-label="customer_row_b2, Bob">Bob</div>
+      <div id="customer_row_a1" data-testid="customer-row" aria-label="customer_row_a1, Alice">Alice</div>
+      <div id="customer_row_b2" data-testid="customer-row" aria-label="customer_row_b2, Bob">Bob</div>
       <div id="supplier_row_c3" aria-label="supplier_row_c3, Carol">Carol</div>
     </div>
   </body>