Handle WebView assets correctly when multiple APKs are used.

Add all splits and shared libraries used by the WebView implementation
to the application's asset path, instead of just the base APK. Fix the
asset manipulation code path in WebViewFactory to reuse the modern
implementation in WebViewDelegate (using appendLibAssetForMainAssetPath)
instead of relying on addAssetPathAsSharedLibrary.

Add a new variant of appendLibAssetForMainAssetPath which accepts
multiple paths at once, to make it more efficient.

Bug: 124116212
Test: atest CtsWebkitTestCases
Change-Id: Ie55525d78089a4595c5b0b126e4ff1530303afe8