Revert "Disable flaky TaskManagerBrowserTest.NoticeHostedAppTab*Reload on Linux."

This reverts commit ddbd49f9.

Reason for revert:
CL:1879255 is causing the flakiness and is reverted (CL:1904504).
Revert this CL to re-enable the tests.

Original change's description:
> Disable flaky TaskManagerBrowserTest.NoticeHostedAppTab*Reload on Linux.
> 
> TBR=afakhry@chromium.org
> 
> Bug: 1021553
> Change-Id: I6d6170beb77d08da192d24e7ebb7246a83926a7b
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1899334
> Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
> Commit-Queue: Joshua Pawlicki <waffles@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#712622}

TBR=waffles@chromium.org,afakhry@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1021553
Change-Id: I1fe435871e401d46cff04c1e16604214e3d2ea43
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1904215Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713692}

chrome/browser/task_manager/task_manager_browsertest.cc

@@ -516,15 +516,7 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeHostedAppTabChanges) {
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(0, MatchAnyApp()));
 }
 
-// Flaky - crbug.com/102553
-#if defined(OS_LINUX)
-#define MAYBE_NoticeHostedAppTabAfterReload \
-  DISABLED_NoticeHostedAppTabAfterReload
-#else
-#define MAYBE_NoticeHostedAppTabAfterReload NoticeHostedAppTabAfterReload
-#endif
-IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest,
-                       MAYBE_NoticeHostedAppTabAfterReload) {
+IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeHostedAppTabAfterReload) {
   // The app under test acts on URLs whose host is "localhost",
   // so the URLs we navigate to must have host "localhost".
   GURL base_url = embedded_test_server()->GetURL(
@@ -554,15 +546,7 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest,
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(0, MatchAnyExtension()));
 }
 
-// Flaky - crbug.com/102553
-#if defined(OS_LINUX)
-#define MAYBE_NoticeHostedAppTabBeforeReload \
-  DISABLED_NoticeHostedAppTabBeforeReload
-#else
-#define MAYBE_NoticeHostedAppTabBeforeReload NoticeHostedAppTabBeforeReload
-#endif
-IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest,
-                       MAYBE_NoticeHostedAppTabBeforeReload) {
+IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeHostedAppTabBeforeReload) {
   // The app under test acts on URLs whose host is "localhost",
   // so the URLs we navigate to must have host "localhost".
   GURL base_url = embedded_test_server()->GetURL(