Remove on-by-default flag --harmony-object

test/js-perf-test/JSTests.json

 {
   "name": "JSTests",
   "run_count": 5,
   "run_count_android_arm": 3,
   "run_count_android_arm64": 3,
   "timeout": 120,
   "units": "score",
   "total": true,
   "resources": ["base.js"],
   "tests": [
@@ skipping 95 matching lines @@
         {"name": "Untagged"},
         {"name": "LargeUntagged"},
         {"name": "Tagged"}
       ]
     },
     {
       "name": "Object",
       "path": ["Object"],
       "main": "run.js",
       "resources": ["assign.js"],
-      "flags": ["--harmony-object"],
       "results_regexp": "^%s\\-Object\\(Score\\): (.+)$",
       "tests": [
         {"name": "Assign"}
       ]
     },
     {
       "name": "Scope",
       "path": ["Scope"],
       "main": "run.js",
       "resources": ["with.js"],
       "results_regexp": "^%s\\-Scope\\(Score\\): (.+)$",
       "tests": [
         {"name": "With"}
       ]
     },
     {
       "name": "Exceptions",
       "path": ["Exceptions"],
       "main": "run.js",
       "resources": ["try-catch.js"],
       "results_regexp": "^%s\\-Exceptions\\(Score\\): (.+)$",
       "tests": [
         {"name": "Try-Catch"}
       ]
     }
   ]
 }