Remove enable lazy load flag from virtual tests

The feature is enabled by default, so we don't need to use the feature
flag that enables it.

Bug: N/A
Change-Id: I7d404fdbf0111ffc8b94fc8afc75a84a8a3eb944
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2258341Reviewed-by: Scott Little <sclittle@chromium.org>
Commit-Queue: Dominic Farolino <dom@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781931}

third_party/blink/web_tests/VirtualTestSuites

@@ -437,7 +437,7 @@
   {
     "prefix": "lazyload-image",
     "bases": ["http/tests/lazyload"],
-    "args": ["--enable-blink-features=LazyImageLoading,AutomaticLazyImageLoading",
+    "args": ["--enable-blink-features=AutomaticLazyImageLoading",
              "--disable-blink-features=RestrictAutomaticLazyImageLoadingToDataSaver"]
   },
   {

third_party/blink/web_tests/virtual/lazyload-image/http/tests/lazyload/README.txt

 # This suite runs the tests in http/tests/lazyload with
-# --enable-features=LazyImageLoading.
+# --enable-features=AutomaticLazyImageLoading.