Re-enable CopyBetweenWindows/FilesAppBrowserTest in RELEASE

Intermittent flakes in this test was caused by a V8 roll crrev/566206.
Refer to the bug for reproduction steps and regression analysis.

Symptoms were that JS Array return types would sometimes appear in the
test code as being undefined or have no .length property, which caused
intermittent JS exceptions in the test code and hence test failure.

The issue has been fixed in V8 and no longer reproduces @ crrev/567688
ToT. Re-enabling this test RELEASE therefore <eom>.

Tbr: sashab
Bug: 852246
Change-Id: If093f3357042e5e5dec7b399d373ba56e86dafea
Reviewed-on: https://chromium-review.googlesource.com/1102837Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567718}

chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

@@ -365,14 +365,8 @@ WRAPPED_INSTANTIATE_TEST_CASE_P(
                       TestCase("openFileDialogCancelDrive"),
                       TestCase("openFileDialogEscapeDrive")));
 
-// Flaky in RELEASE - https://crbug.com/852246
-#if defined(NDEBUG)
-#define MAYBE_CopyBetweenWindows DISABLED_CopyBetweenWindows
-#else
-#define MAYBE_CopyBetweenWindows CopyBetweenWindows
-#endif
 WRAPPED_INSTANTIATE_TEST_CASE_P(
-    MAYBE_CopyBetweenWindows, /* copy_between_windows.js */
+    CopyBetweenWindows, /* copy_between_windows.js */
     FilesAppBrowserTest,
     ::testing::Values(TestCase("copyBetweenWindowsLocalToDrive"),
                       TestCase("copyBetweenWindowsLocalToUsb"),