[Payments][Android] Enable flaky delegation tests.

This cl enables PaymentHandlerEnableDelegationsTest tests after removing
"PaymentRequestTestRule.ENABLE_EXPERIMENTAL_WEB_PLATFORM_FEATURES"

I tried reproducing the flakes locally by copying trybot's gn args and
running tests 100 times on a Nexus 5, and Pixel 3, I couldn't reproduce
any flakes.

Looking at the stack trace of some of the crashes(see the
link below) I suspected that the crash might be related to one of the
experimental service worker features enabled by the experimental web
platform features.
https://bugs.chromium.org/p/chromium/issues/detail?id=1054103#c7

Change-Id: I7b74752034f6540aff25df4a1f0e3cdb9366086b
Bug: 1054103
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2115875Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
Commit-Queue: Sahel Sharify <sahel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752496}

chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentHandlerEnableDelegationsTest.java

@@ -18,7 +18,6 @@ import org.junit.runner.RunWith;
 
 import org.chromium.base.test.util.CallbackHelper;
 import org.chromium.base.test.util.CommandLineFlags;
-import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.flags.ChromeSwitches;
@@ -30,8 +29,7 @@ import org.chromium.ui.test.util.DisableAnimationsTestRule;
 
 /** An integration test for shipping address and payer's contact information delegation. */
 @RunWith(ChromeJUnit4ClassRunner.class)
-@CommandLineFlags.Add({ChromeSwitches.DISABLE_FIRST_RUN_EXPERIENCE,
-        PaymentRequestTestRule.ENABLE_EXPERIMENTAL_WEB_PLATFORM_FEATURES})
+@CommandLineFlags.Add({ChromeSwitches.DISABLE_FIRST_RUN_EXPERIENCE})
 @MediumTest
 public class PaymentHandlerEnableDelegationsTest {
     // Disable animations to reduce flakiness.
@@ -86,7 +84,6 @@ public class PaymentHandlerEnableDelegationsTest {
 
     @Test
     @Feature({"Payments"})
-    @DisabledTest(message = "Test is flaky, see crbug.com/1054103")
     @MediumTest
     public void testShippingDelegation() throws Throwable {
         installPaymentHandlerWithDelegations("['shippingAddress']");
@@ -100,7 +97,6 @@ public class PaymentHandlerEnableDelegationsTest {
 
     @Test
     @Feature({"Payments"})
-    @DisabledTest(message = "Test is flaky, see crbug.com/1054108")
     @MediumTest
     public void testContactDelegation() throws Throwable {
         installPaymentHandlerWithDelegations("['payerName', 'payerEmail', 'payerPhone']");
@@ -116,7 +112,6 @@ public class PaymentHandlerEnableDelegationsTest {
 
     @Test
     @Feature({"Payments"})
-    @DisabledTest(message = "Test is flaky, see crbug.com/1054062")
     @MediumTest
     public void testShippingAndContactInfoDelegation() throws Throwable {
         installPaymentHandlerWithDelegations(