Fix use-after-move in //base/test/

Fix use-after-move (potential) bugs found by the
"bugprone-use-after-move" clang-tidy check.

Bug: 1122844
Change-Id: I9515efae60d93ede65aa3b8de11f6ee05828e109
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2382812
Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802930}

base/test/task_environment.cc

@@ -780,15 +780,15 @@ void TaskEnvironment::TestTaskTracker::RunTask(internal::Task task,
     // watching for tests that have actually long running tasks which cause our
     // test suites to run slowly.
     base::TimeTicks before = base::subtle::TimeTicksNowIgnoringOverride();
+    const Location posted_from = task.posted_from;
     internal::ThreadPoolImpl::TaskTrackerImpl::RunTask(std::move(task),
                                                        sequence, traits);
     base::TimeTicks after = base::subtle::TimeTicksNowIgnoringOverride();
 
     if ((after - before) > TestTimeouts::action_max_timeout()) {
       ADD_FAILURE() << "TaskEnvironment: RunTask took more than "
                     << TestTimeouts::action_max_timeout().InSeconds()
-                    << " seconds. "
-                    << "Posted from " << task.posted_from.ToString();
+                    << " seconds. Posted from " << posted_from.ToString();
     }
   }