Remove use of MAC_OS_X_VERSION_10_*

This changes expectations based on the macOS SDK used to build
Chromium. Chromium has required newer than the 10.12 SDK for years,
so remove this.

Bug: 1044838
Change-Id: I41deec339d7da73392c410dbdb1439a824c0f81f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2015361
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Auto-Submit: Avi Drissman <avi@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734638}

chrome/browser/picture_in_picture/picture_in_picture_window_controller_browsertest.cc

@@ -223,8 +223,7 @@ IN_PROC_BROWSER_TEST_F(PictureInPictureWindowControllerBrowserTest,
   auto* overlay_window = window_controller()->GetWindowForTesting();
   gfx::NativeWindow native_window =
       static_cast<OverlayWindowViews*>(overlay_window)->GetNativeWindow();
-#if defined(OS_CHROMEOS) || \
-    (defined(MAC_OS_X_VERSION_10_12) && !defined(MAC_OS_VERSION_10_13))
+#if defined(OS_CHROMEOS)
   EXPECT_FALSE(platform_util::IsWindowActive(native_window));
 #else
   EXPECT_TRUE(platform_util::IsWindowActive(native_window));