[WebLayer] Fix browsertests crashing on Android

These were broken from http://crrev.com/c/1854204

Change-Id: I566c48d4f3c03708d56280804e750563189257d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864517
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Auto-Submit: Clark DuVall <cduvall@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706707}

testing/test.gni

@@ -99,6 +99,7 @@ template("test") {
         "min_sdk_version",
         "proguard_configs",
         "proguard_enabled",
+        "shared_resources",
         "srcjar_deps",
         "target_sdk_version",
         "use_default_launcher",

weblayer/test/BUILD.gn

@@ -121,5 +121,6 @@ test("weblayer_browsertests") {
         "${target_gen_dir}/weblayer_browsertests_manifest/AndroidManifest.xml"
     android_manifest_dep = ":weblayer_browsertests_manifest"
     use_default_launcher = false
+    shared_resources = true
   }
 }