Mark weblayer_support_apk as never_incremental.

We never added support to the test infra for having "additional_apks" be
incremental apks.

Change-Id: I51ec92db0eeb807fcd8daad3760bb309d50cba8c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1881309
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709522}

weblayer/shell/android/BUILD.gn

@@ -210,6 +210,9 @@ jinja_template("weblayer_support_manifest") {
 android_apk("weblayer_support_apk") {
   testonly = true
   
+  # Test runner does not support having "additional apks" that are incremental.
+  never_incremental = true
+
   deps = [
     ":weblayer_support_manifest",
     "//android_webview:locale_pak_assets",