[ios] Realign test arguments for EG and EG_CQ tests

The iOS generate wrapper template sets xctest and xcode
parallelization to true (in ios/third_party/earl_grey/ios_eg_test.gni.
Some EG tests don't utilize xctest, so we want to explicitly
turn those off.

Setting xctest = false for those tests in .gn files.
Adding the test-arg for ios_chrome_settings_egtest in the manner
that run.py expects it in.

Change-Id: Id5ee79f08a34c4e9e3db84769287ee51b735bd29
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2112750Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Jeff Yoon <jeffyoon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752574}

ios/chrome/test/earl_grey/BUILD.gn

@@ -39,6 +39,8 @@ chrome_ios_eg_test("ios_chrome_integration_egtests") {
     "//ios/chrome/browser/ui/autofill/manual_fill:eg_tests",
     "//ios/chrome/browser/ui/content_suggestions:eg_tests",
   ]
+
+  xctest = false
 }
 
 chrome_ios_eg_test("ios_chrome_autofill_automation_egtests") {
@@ -71,6 +73,12 @@ chrome_ios_eg_test("ios_chrome_settings_egtests") {
     "//ios/chrome/browser/ui/settings/language:eg_tests",
     "//ios/chrome/browser/ui/settings/password:eg_tests",
   ]
+
+  executable_args = [
+    "--args-json",
+    "{\"test_args\": [\"--enable-features=ClearSyncedData\",]}",
+  ]
+  xctest = false
 }
 
 chrome_ios_eg_test("ios_chrome_ui_egtests") {
@@ -103,6 +111,7 @@ chrome_ios_eg_test("ios_chrome_ui_egtests") {
   ]
 
   shards = 2
+  xctest = false
 }
 
 chrome_ios_eg_test("ios_chrome_web_egtests") {