Disabled flaky AutoEnrollment-related ChromeOS tests.

These tests have been flaking for a long time now, crashing with
segfaults occasionally on the linux-chromeos-rel bot for at least a week
now:

https://ci.chromium.org/p/chromium/builders/ci/linux-chromeos-rel?limit=200

See the bug for more details.

TBR=antrim@chromium.org

Bug: 992022
Change-Id: I9074436363e6bbef0dfa838274a1343e9e333f84
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1745288Reviewed-by: Scott Little <sclittle@chromium.org>
Commit-Queue: Scott Little <sclittle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685374}

chrome/browser/chromeos/login/enrollment/enrollment_local_policy_server_browsertest.cc

@@ -552,14 +552,17 @@ IN_PROC_BROWSER_TEST_F(AutoEnrollmentNoStateKeys, FREExplicitlyRequired) {
 
 // FRE not explicitly required and the state keys are missing. Should proceed to
 // normal signin.
-IN_PROC_BROWSER_TEST_F(AutoEnrollmentNoStateKeys, FRENotRequired) {
+// Test is flaky, and crashes occasionally. https://crbug.com/992022
+IN_PROC_BROWSER_TEST_F(AutoEnrollmentNoStateKeys, DISABLED_FRENotRequired) {
   host()->StartWizard(AutoEnrollmentCheckScreenView::kScreenId);
   OobeScreenWaiter(GaiaView::kScreenId).Wait();
 }
 
 // FRE explicitly not required in VPD, so it should not even contact the policy
 // server.
-IN_PROC_BROWSER_TEST_F(AutoEnrollmentWithStatistics, FREExplicitlyNotRequired) {
+// Test is flaky, and crashes occasionally. https://crbug.com/992022
+IN_PROC_BROWSER_TEST_F(AutoEnrollmentWithStatistics,
+                       DISABLED_FREExplicitlyNotRequired) {
   SetFRERequiredKey("0");
 
   // Should be ignored.
@@ -574,7 +577,9 @@ IN_PROC_BROWSER_TEST_F(AutoEnrollmentWithStatistics, FREExplicitlyNotRequired) {
 }
 
 // FRE is not required when VPD is valid and activate date is not there.
-IN_PROC_BROWSER_TEST_F(AutoEnrollmentWithStatistics, MachineNotActivated) {
+// Test is flaky, and crashes occasionally. https://crbug.com/992022
+IN_PROC_BROWSER_TEST_F(AutoEnrollmentWithStatistics,
+                       DISABLED_MachineNotActivated) {
   // Should be ignored.
   EXPECT_TRUE(policy_server_.SetDeviceStateRetrievalResponse(
       state_keys_broker(),