Disable testContextMenuOpenInNewTabFromTallPage on simulator

This test was already failing and disabled on device. It is now failing on
iPhone X simulator as well for the same reason so disabling it on
simulator as well.

Bug: 755888
Change-Id: I13ab73aa46a4698ff8c50cea1d786a9c1f5e4a85
Tbr: noyau@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/684312Reviewed-by: Elodie Banel <lod@chromium.org>
Reviewed-by: Eric Noyau <noyau@chromium.org>
Commit-Queue: Elodie Banel <lod@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504369}

ios/chrome/browser/context_menu/context_menu_egtest.mm

@@ -199,11 +199,9 @@ void SelectTabAtIndexInCurrentMode(NSUInteger index) {
 // current screen view.
 - (void)testContextMenuOpenInNewTabFromTallPage {
 // TODO(crbug.com/755888): Reenable this test.
-#if !TARGET_IPHONE_SIMULATOR
   if (!IsIPadIdiom()) {
     EARL_GREY_TEST_DISABLED(@"Failing constently on iPhone devices.");
   }
-#endif
 
   // Set up test simple http server.
   std::map<GURL, std::string> responses;