Reorganize tests and benchmark scripts.

Mainly to get rid of one top level directory. But this will
also be useful when there are tests of the embedding API.

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