Fix closures in methods.

A local name inside a method should always resolve to a self send even
if there is a local variable with that name outside of the method.

test/language/closure/closed_closure_in_method.wren

@@ -1,17 +0,0 @@
-// TODO: Is this right? Shouldn't it resolve to this.local?
-var foo = null
-
-{
-  var local = "local"
-  class Foo {
-    construct new() {}
-
-    method {
-      System.print(local)
-    }
-  }
-
-  foo = Foo.new()
-}
-
-foo.method // expect: local

test/language/closure/open_closure_in_method.wren

@@ -1,13 +0,0 @@
-// TODO: Is this right? Shouldn't it resolve to this.local?
-{
-  var local = "local"
-  class Foo {
-    construct new() {}
-
-    method {
-      System.print(local)
-    }
-  }
-
-  Foo.new().method // expect: local
-}