fix(dart/transform): Fix DirectiveMetadata read tests

Author: Tim Blasi

modules/angular2/test/transform/template_compiler/one_directive_files/hello.ng_meta.json

@@ -5,7 +5,7 @@
  "selector":"hello-app",
  "compileChildren":true,
  "hostListeners":{},
- "hostProperties":[],
+ "hostProperties":{},
  "properties":[],
  "readAttributes":[],
  "type":1,

modules/angular2/test/transform/template_compiler/with_prefix_files/goodbye.ng_meta.json

@@ -4,7 +4,7 @@
  "selector":"goodbye-app",
  "compileChildren":true,
  "hostListeners":{},
- "hostProperties":[],
+ "hostProperties":{},
  "properties":[],
  "readAttributes":[],
  "type":1,