Disable PrerenderTaskManager. It's flaky on Win (dbg).

chrome/browser/prerender/prerender_browsertest.cc

Index: chrome/browser/prerender/prerender_browsertest.cc
diff --git a/chrome/browser/prerender/prerender_browsertest.cc b/chrome/browser/prerender/prerender_browsertest.cc
index e9a0955fe05c0339f0080eda5507e86187b77eee..24d471de4d6cae5e6cb7d8931fcca025a6fcf4be 100644
--- a/chrome/browser/prerender/prerender_browsertest.cc
+++ b/chrome/browser/prerender/prerender_browsertest.cc
@@ -1486,7 +1486,8 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderInfiniteLoopMultiple) {
   EXPECT_FALSE(UrlIsPendingInPrerenderManager(kHtmlFileC));
 }
 
-IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderTaskManager) {
+// See crbug.com/131836.
+IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, DISABLED_PrerenderTaskManager) {
   // Show the task manager. This populates the model.
   current_browser()->window()->ShowTaskManager();
   // Wait for the model of task manager to start.