[iOS] Disable testUserAgentTypeInPreviousLoad

The test is flaky.

Bug: 1110048, 1110890
Change-Id: I1a0613d4f33df0f22472733e8238f6c16b507714
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2324849
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792757}

ios/chrome/browser/prerender/prerender_egtest.mm

@@ -183,7 +183,8 @@ GREYElementInteraction* RequestDesktopButton() {
 
 // Tests that tapping the prerendered suggestions keeps the UserAgent of the
 // previous page.
-- (void)testUserAgentTypeInPreviousLoad {
+// TODO(crbug.com/1110890): Test is flaky.
+- (void)DISABLED_testUserAgentTypeInPreviousLoad {
   [self addURLToHistory];
   const GURL pageURL = self.testServer->GetURL(kPageURL);
   NSString* pageString = base::SysUTF8ToNSString(pageURL.GetContent());