Move the hr-time directory from web-platform-tests/ to wpt/.

third_party/WebKit/LayoutTests/imported/wpt/hr-time/basic.worker.js

 importScripts("/resources/testharness.js");
 
 test(function() {
   assert_true((performance !== undefined), "WorkerGlobalScope.performance exists");
   assert_equals((typeof performance.now), "function");
 }, "WorkerGlobalScope.performance.now() is a function");
 
 test(function() {
   assert_true(performance.now() > 0);
 }, "WorkerGlobalScope.performance.now() returns a positive number");
 
 test(function() {
     var now1 = performance.now();
     var now2 = performance.now();
     assert_true((now2-now1) >= 0);
   }, "WorkerGlobalScope.performance.now() difference is not negative");
 
 done();