refactor: move benchmark directory under test and update all references

The benchmark directory is relocated from the project root into the test directory, and all scripts, documentation links, and gitignore paths are updated accordingly. The test runner is also refactored to explicitly walk subdirectories (core, io, language, limit) instead of using a single test root, and a new test/README.md is added to document the test suite structure. Additionally, the constructor test for the Foo class is updated to add a zero-arity constructor and adjust expected output strings.

test/language/inheritance/inherited_fields_in_closure.wren

@@ -0,0 +1,36 @@
+class Foo {
+  new { _field = "Foo field" }
+
+  closeOverFooGet {
+    return new Fn { new Fn { _field } }
+  }
+
+  closeOverFooSet {
+    return new Fn { new Fn { _field = "new foo value" } }
+  }
+}
+
+class Bar is Foo {
+  new {
+    super
+    _field = "Bar field"
+  }
+
+  closeOverBarGet {
+    return new Fn { new Fn { _field } }
+  }
+
+  closeOverBarSet {
+    return new Fn { new Fn { _field = "new bar value" } }
+  }
+}
+
+var bar = new Bar
+IO.print(bar.closeOverFooGet.call().call()) // expect: Foo field
+IO.print(bar.closeOverBarGet.call().call()) // expect: Bar field
+bar.closeOverFooSet.call().call()
+IO.print(bar.closeOverFooGet.call().call()) // expect: new foo value
+IO.print(bar.closeOverBarGet.call().call()) // expect: Bar field
+bar.closeOverBarSet.call().call()
+IO.print(bar.closeOverFooGet.call().call()) // expect: new foo value
+IO.print(bar.closeOverBarGet.call().call()) // expect: new bar value