Reland "[Sheriffing] Disable AppShimInteractiveTest.Launch (mac) due to flakiness."

This reverts commit 00c1b7ab.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Revert "[Sheriffing] Disable AppShimInteractiveTest.Launch (mac) due to flakiness."
> 
> This reverts commit 0c873bf2.
> 
> Reason for revert: Fix for flake in crrev.com/615269
> 
> Original change's description:
> > [Sheriffing] Disable AppShimInteractiveTest.Launch (mac) due to flakiness.
> > 
> > Tbr: ccameron@chromium.org
> > Bug: 913490
> > Change-Id: I90fabcfe3bba129fbe2786738c3757526b423a6f
> > Reviewed-on: https://chromium-review.googlesource.com/c/1369721
> > Commit-Queue: Samuel Huang <huangs@chromium.org>
> > Reviewed-by: Samuel Huang <huangs@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#615159}
> 
> TBR=huangs@chromium.org,ccameron@chromium.org
> 
> Change-Id: I1326fab24c9d4d85bbd66b8b48b60f8471b86593
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 913490
> Reviewed-on: https://chromium-review.googlesource.com/c/1370571
> Reviewed-by: ccameron <ccameron@chromium.org>
> Commit-Queue: ccameron <ccameron@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#615274}

TBR=huangs@chromium.org,ccameron@chromium.org

Change-Id: I72829b7b404a571095123f2ffd028ff189563ee8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 913490
Reviewed-on: https://chromium-review.googlesource.com/c/1371931Reviewed-by: ccameron <ccameron@chromium.org>
Commit-Queue: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615570}

chrome/browser/apps/app_shim/app_shim_interactive_uitest_mac.mm

@@ -303,7 +303,7 @@ namespace apps {
 #define MAYBE_ShowWindow DISABLED_ShowWindow
 #define MAYBE_RebuildShim DISABLED_RebuildShim
 #else
-#define MAYBE_Launch Launch
+#define MAYBE_Launch DISABLED_Launch  // http://crbug.com/913490
 #define MAYBE_HostedAppLaunch DISABLED_HostedAppLaunch
 #define MAYBE_ShowWindow ShowWindow
 // http://crbug.com/517744 HostedAppLaunch fails with open as tab for apps